To offend a group of peers through the means of acting a fool
or just straight up buggin out
or to make ones self look bad at inappropriate times and angering an opposing party.
Grandma: "happy birthday billy hope you enjoy your present"
billy: "socks again, oh man Grandma you be set trippin!"
A certain 'hood, or block may be refered to as a "Set".
"What set you from, Nigga?"
Any gang violence or rivalry between "Sets" can be labeled as "Set Trippin".
"Homeboy from projects got killed by some set trippin ass niggas from the northside."
"Take that shit to the street, we aint set trippin up in here!"
acting out of place or against a "set" or peer group while amongst them
Johnny was playing cards with the kids down the street and tried to make up his own rules but they wouldn't have it because he was set trippin