I learned about がる from two different native teachers and both explained it differently. The first one said that がる is seemed/looks like someone wants something
The cat seems to want it
We act like we wanted anything (and everything)
The other one said it is not "seems" it more like, "tendency to do X" and that we don't have a similar concept in English.
My father had the tendency to smoke a lot.
So I want to ask, which explain is the right one? Are they both right?