yeah it was just for the contest but sometimes he is envious if vegeta win against him in JANKEN so as to who will take the first fight ^^ it was in majin buu saga ^^
its impossible to avoid envious if it was like that. most of these sins can't be avoided. gluttony can. wrath comes eventually but is nearly impossible to avoid, pride is impossible to avoid when you feel proud of something like a son or sister it builds up your pride you would have to have low standards to avoid it. i could deduce the rest but really i would rather not.