Creativity is ultimately personal. When being creative, you are making something unique and new. You may have taken inspiration from other sources, but the end product is uniquely your own. Humans are constantly being innovative and inventive, and everyone is capable of this in their own way. However, this end product is more often than not, subjective. Be it a song, a painting, a poem, an outfit or even just an idea, there is no guarantee that people will like it. Everyone's opinion is different, and what appeals to one may not to another.
People are perfectly entitled to have these opinions. No one should be coerced into pretending to like or dislike something, when that's not true. Buckling to the expectations or opinions of others stifles and prevents your own creativity. Being able to express your own opinion is vital to embracing your individuality, and whatever creations or artistic expression that may lead to. There is also the very difficult, but important distinction to make between which creations you like, and which are actually good. Sometimes you have to admit to the talent behind a work, even if you don't like it in an overall sense.
What we should remember though, is that behind every artwork or creation there is a person. A human being, like you or I, with real emotions. Creativity is a personal matter, and to put your own creation, in whatever medium it may be, out into the world for others to see takes a certain degree of courage. It is placing oneself in a vulnerable position, choosing to open themselves up to the world in this way - some going deeper in their personal expression than others of course. People have to expect criticism of their creations though, both good and bad. But what both critic and artist should remember is to keep criticism impersonal. This sounds contradictory, given the personal nature of creativity. However, criticism should be constructive, not merely slanderous, and restrict itself to that particular piece of work, not making reference to the person behind it. There should be a separation of artist and work: for instance, someone may be your friend, but you could hate their work. Or, there's the inverse - disliking a person, but enjoying what they have produced. We can discuss the ways in which the artist's life and attitude may have influenced the work - as long as we refrain from making negative remarks about said person and their life. However, the artist in question should also remember not take criticism of their work too personally and allow it to dishearten them, but instead remember that it is merely one person's opinion.
I think it's important to remember the bravery it takes to share your creations, as nowadays it's all too easy to use the internet to post unnecessarily cruel comments, forgetting that there's a person reading them at the other end. The internet gives us anonymity, which is a powerful thing and should not be misused. It's perfectly alright to dislike someone's work, as long as you do so respectfully. Bear in mind that art is highly personal and subjective, there is no right or wrong opinion regarding any creation or piece of work, but never insult or be unnecessarily mean to someone who has willingly opened themselves up for the world to see.