Likes and dislikes often reveal a great deal about a character, especially why they like or dislike something. This can be a good way to create back story for the character.
For example, Character A dislikes sprouts because their mother made them eat them as a child, so what did they do to get around this? Did it lead to huge rows between them and their mother? Or did they wait till they left home and ditched the sprouts forever? Was their mother a dominating woman or was the child being unreasonable because Mum only offered sprouts once a year and didn't force them on anyone (this being a child's faulty perception/memory)? Lots of information could be revealed here just from this one example (not least how Character A deals with things they don't like!).
Sometimes of course we like or dislike things/people etc because "we just do" but for a character there does need to be a more solid reason than that, even if other characters consider that reason flimsy.