Likes have different meanings for people and it always depends how does it work. Some don't care about those nor give them out. Others do that often, especially under posts, but majority of users rather stay with that moderately. If you do or say something good and you get many likes, that means people appreciate it. This involves art, literature, agreeing with opinions or suggestions, etc. Also there are witty comments that either are pretty accurate or make us laugh. Nice vines, same, well argumented opinions, sometimes showing that given person didn't save words and uses rich vocabulary as well.
"Not liking" people usually treat it solely just as a number that is an empty count. They might never give them or do that on extremely occasions, that is quite dependant. They also either tend to not agree with most of what others say or just not display it that way.
Giving too much of them ( every single post ), isn't the good way to go, since they go undervalued, thus they stop to mean much and a person ends up having way too many of them, for no reason.
And me? I'm one the those people who sometimes click the that button. When I "like" something, logically speaking. Mostly being a good drawing, literature and either something funny or sharing the same opinion.