reasons for guys finishing quickly?

i (25F) just started casually hooking up and one thing that bothers me is that all the guys (caucasians 💀 bc i live in the states) i hooked up with ay mabibilis labasan. i know i’m not unattractive because i get compliments from strangers that i’m pretty. but i can’t help but overthink na at the end of the deed, they finish easily kasi they just want to get it over with or they didn’t enjoy it. what are the other reasons for guys to cum quickly? and for me to enjoy casual sex?