When someone is going to do something really stupid, useless
, or annoying, or if you are jealous
that someone is getting to do something you're not, it is a put-down. See whatever
geek: Well, I'M going to get my hair follicle tested for carbon today!
: Psh, have fun.
Annie: guess what, i get a free shopping spree
at neiman marcus
Jenna: psh, have fun.