What does montarse películas mean?
Expression
to make a whole drama out of it in your head
Building a story in your head that does not exist: an offence nobody committed, a romance nobody suggested, a catastrophe that is not going to happen. Also much used in the first person, to own up to it: me monté una película yo sola. It often takes an intensifier — se monta cada película… — and que no veas, meaning "beyond belief", is a common one.
No te montes películas, solo te ha dado las gracias.
