What a like means

When people click the like button on a post, it can mean very different things. For example:

I like that piece.
I like that person.
I want to help them get more visibility.
I want the message to get more visibility.
I need to redo the favor because they liked my post, too.
I want them to see that I clicked like.
I want others to see that I like the post.
Everyone seems to like it so I should like it, too.

What would you add? Which of those apply to your liking habits?