Caer bien/mal = to like/dislike (someone)
A common way to express that you like someone is by using the phrase caer bien. This phrase requires an indirect object (me, te, le, nos, or les), depending on who is doing the liking. Using the pronoun me, for example, indicates that I am doing the liking.
| Me cae bien el profesor. | I like the professor. |
In the previous example, me does not mean I. Rather, it suggests that the professor is liked by me.
| Les cae bien su dentista. | They like their dentist. |
Here les does not mean they. Instead, it identifies that their dentist is liked by them.
Caer is conjugated based who is being liked: cae for a single person and caen for more than one person.
| Tu amiga me cae bien. | I like your friend. |
| Tus amigas me caen bien. | I like your friends. |
If you want to say you don't like someone, use caer mal.
| Me caen mal los profesores. | I don't like the professors. |
The phrase caer bien/mal literally means: to fall on someone well/poorly and is most often associated with (dis)liking people, not things.