Risks are curious things. Some of us are paid to take them, some of us make careers out of quantifying them, but for the large part, most of us are hopeless at assessing the risks we take daily.
Anyone who's ever woken in a cold sweat remembering something that with hindsight was eye-poppingly stupid will know what I mean.
So it's no surprise that when it comes to the least rational, the most passionate part of our lives - sex - that our assessment of risk is somewhat on the optimistic side.
Research published this week by Marie Stopes shows that of 4,000 adults not trying for a baby, a third of women and almost half of the men had unprotected sex at least once in the past year.
And here's the surprising part. Around eight out of 10 of those having unprotected sex said they believed it was "very unlikely" that it would result in pregnancy or they'd contract a sexually transmitted infection.
When it comes to our sex lives, it seems we cross our fingers and hope for the best. It won't happen to me.
Yet 185,000 women accessed abortion services last year, which suggests that for quite a lot of us, it does happen. Half a million STIs were diagnosed last year too, some of them incurable and life-threatening.
That's quite a lot of people who got unlucky, and while an STI or unplanned pregnancy are not the inevitable consequences of unprotected sex, they are very real risks.
Delve a little further, though, and things get really interesting. It seems the older we get, the less likely we are to worry about those consequences.
Fewer 18-24-year-olds (just 18%) have unprotected sex than other age groups, and far fewer of them think they're invulnerable if they do. You read that right - The Youth, today, appear to be the more sensible ones.
The over 50s are probably right not to worry about pregnancy. But they're smack bang in middle of the fastest growing age-group of people living with HIV and levels of STIs are also on the increase.
Back to the 18-24-year-olds for a moment though. They're justified in being concerned because young people have for years been disproportionally affected by sexual ill health. One in nine sexually active people in this age group has chlamydia, and 22 is the most common age to seek abortion.
This age-group has been the target of government sexual health campaigns and the Teenage Pregnancy Strategy and it's heartening to see them taking risks more seriously than those with older heads on their shoulders.
And what of those outside this survey and still at school? Just think what a gift we'd give them if we put Relationships and Sex Education on the National Curriculum.
If we can consider teaching them Ancient Greek, surely the skills to enjoy healthy relationships should get a look-in too?
The truth is, we all take risks with our health from time to time and public health messaging goes right out of the window at Christmas. It's the season to eat, drink and be merry, and now here we are in cold, wet January.
The bars are empty, the gyms and sexual health clinics are full to bursting, and calls to Marie Stopes from women worried about unplanned pregnancy will increase by 10% for the next few weeks.
Some risks are worth taking. For those that really aren't, we have contraception and condoms. So if you've been meaning to find a better method of contraception, now's the time to make that appointment, and don't forget condoms to prevent infections.
Wishing you all a very healthy and happy 2014.