1. I may grow old but I will never "wear the bottom of my trousers rolled", unless I'm at the beach. Partly, because I'm not an east London hipster, but mostly because I am six feet four inches tall and spent my entire childhood wearing ankle flappers because of poverty, not style.
2. If you're born male into an Italian family, you will always be so in touch with your feminine side that even your own daughters will suspect that you are secretly gay.
3. If you are born into that same Italian family and grow up eating antipasti, primi, secondi and gelato each and every school night, plus home-made pizza and lasagne at the weekend, you will a. have serious issues with restaurant food, service and prices for the rest of your life, b. contribute to the nation's obesity crisis once your metabolism starts slowing down.
4. Your metabolism really does start slowing down in your 30s - so maybe skip the cheese course.
5. Nothing in life is more over-rated than lobster thermidor - apart from maybe Shoreditch, Beaujolais Nouveau and Jeremy Clarkson.
6. Marmite and Twiglets aren't polarising. They are just disgusting, with a hefty marketing budget.
7. I may not have "measured out my life in coffee spoons", but I could do so in rubber chicken black-tie dinners at the Grosvenor House Hotel in London and the Waldorf Astoria in Manhattan. You will not be able to remember anything about the one-before-last black-tie dinner you went to.
8. Follow the advice of the inimitable UK boss of Conde Nast, Nicholas Coleridge, when it comes to parties: turn up early, don't check your coat, grab a non-alcoholic drink and make a beeline for your host to announce your presence, perhaps chat to the guest of honour, and then depart quietly for the next one.
9. I was born into a two-up, two-down with an outdoor loo, where I lived until I was 11 years-old. This was hugely significant in shaping the person I am today. No-one cares.
10. Being born in Croydon and going to the John Fisher School in Purley marks a man - for life. Look at Matthew Wright, or Bill Nighy
11. Rich people's antiques are poor people's junk furniture. The poor prefer to chuck out the chintz and get down to Ikea and buy something lovely and new.
12. The hardest thing about going to University was a. getting in b. the crap food. Only one of these has improved today.
13. I once had a flirtatious moment involving balloons and a cupboard with Uma Thurman at a celebrity's children's party in New York. It lasted 30 seconds. You can dine out on stories like this for decades.
14. I also once found myself at a sushi counter next to Margaret Thatcher. I offered, earnestly, to help her with her chopsticks. She nearly tore my head off with indignation and then hissed at Jeffrey Archer to pull Denis away from the saki fountain. There's no smoke without fire.
15. No adult straight man who isn't "on the pull" chooses to find himself on a dance floor, sober.
16. Karaoke always sounds better in advance, before you leave the office - never mind before the mic is switched on.
17. There really is no good that can come from being out on the town after 1am - that is, if you're not single.
18. Your mother may sometimes be wrong about the battle, but she is always right about the war. Always.
19. "Most men secretly worry that their wives are crazy, most women secretly worry that their husbands are losers" - Homeland, last weekend. I'm not so sure about the "secretly".
20. The grass is actually hardly ever greener on the other side. It's usually a lot like the Wembley pitch after the American Football matches.
21. We will never stop seeking greener grass.
22. If you can't be with the one you love (honey), then keep looking. Sometimes, you really are never so alone as when in a couple.
23. There is a sound physiological reason why men fall asleep after sex. Women know that too. They just pretend not to.
24. If you go on a family holiday and you have a great time, but the children don't, then it's a crap holiday. If you go on a family holiday and the children love it, but you hate it, it's still a great holiday.
25. None of life's great pleasures turn you more immediately into a smug b*stard than turning left on a plane.
26. Religion, on balance, does more harm than good in the world, but however lapsed, jaundiced and cynical you are: once born a Catholic, you will always describe yourself as a Catholic.
27. If someone puts a meeting in your diary that's more than an hour long, you really don't want to have a meeting with that person.
28. Nostalgia truly is the enemy of progress. Almost nothing we believe isn't as good as it used to be was actually that much better back in the day. Leeds United and TV ads being the exceptions that prove the rule. Rose-tinted spectacles? Should have gone to Specsavers.
29. Never, ever, go into business with family. It will end in tears - and possibly a multi-generational feud whose origins everyone has forgotten. Don't believe me? Watch The Godfather.
30. You can get to the ripe old age of 50, and still not truly understand what a SIPP, ISA, derivative, Credit Default Swap or spread betting really is. Likewise, the Sarbanes-Oxley act or the Duckworth-Lewis method. This doesn't make you a bad person.
31. Knowing what Pi is really is of no use to you in your adult life, no matter what your teachers say. Ditto, Latin and the War of Jenkins Ear. They do not make you a better person.
32. Having hair start growing out of your back, knuckles and - God forbid - ears is really no compensation for losing it up top. Or so I'm told. I'm the only person I know with an advancing hairline.
33. The average woman keeps the same hairdresser for 12 years - which is longer than the average marriage. The only surprise is that some people find this surprising.
34. You will enjoy gigs by bands that never broke up, like The Stones and The Cure, more than bands that split and then reformed - which means virtually any ancient band out there with the honourable exceptions of Take That or Led Zeppelin.
35. Nothing and nobody is ever as cruel in life as a teenage girl can be to her Best Friend Forever.
36. I will never write comedy as funny as Woody Allen, fiction as mesmerising as John Updike, non-fiction as thrilling as Michael Lewis. That's why "I'm still working on" my book.
37. Your children will teach you more than you will ever teach them. If you don't believe that, then you are not listening.
38. If you live with a lame man, you will develop a limp. (It sounds better in Italian).
39. There will never be a better line on a chat show than Caroline Aherne's Mrs Merton to Debbie McGee: "so, what first attracted you to the multi-millionaire Paul Daniels?"
40. It's better to live one day as a lion than a lifetime as a sheep. The two words "Carpe Diem" would have looked ugly in the list on their own.
41. If salt and pepper is good enough for George Clooney then it's good enough for me. But, he really is more salt these days, huh?
42. Most situations in life can be met head on with the aid of a line from The Godfather series: "A man who doesn't spend time with his family can never be a real man".
43. When you think the beautiful, "older woman crush", internationally-acclaimed actress is eyeing you up in the audience from her vantage point on the stage at the Donmar Warehouse, Kristin Scott Thomas really isn't.
44. Never dismiss anyone you see walking towards you in the street as "boring", because you have absolutely no idea how Fifty Shades Of Grey their life is.
45. Only the two people involved ever truly know what goes on inside a marriage - and even then, frequently, only one of them is paying attention.
46. Your children don't need you to be their friends. They have plenty of those, but only two of you. OK, it's 2014 - perhaps they have four of you...
47. Fifty is the new teenage. Only, with money.
48. Within a decade, half the UK population will be 50+; and we already control 79% of disposable wealth. And yet, 96% of us believe that advertising isn't aimed at us at all, perhaps because only 6% of the UK ad industry is over 50. This is madness. It's also a business opportunity.
49. Pedicures are the most pleasure you will ever have with the rest of your clothes on. But not the ones that involve those perverted fish nibbling your toes.
50. "Leave the gun, take the cannoli."
Stefano Hatfield is editor in chief of High50.com