I just want to nominate Vegeta insisting that Goku sloooooowly charge the Genki Dama to maximum power against Kid Buu instead of just teleporting in Mystic Gohan and SSJ3 Gotenks to dogpile ol' Laffy Taffy like even Goku wanted to, on the grounds that it was time that humans finally took some part in defending themselves for once. Like, Vegeta, buddy, pretty much ALL the times that Earth has been in trouble within the last decade+ can be directly blamed on you.
Oh, and there was also post-stick-up-butt Vegeta wasting his Super Saiyajin Blue mode against Cabbe instead of just defeating him in SSJ mode (at a time when Vegeta hadn't mastered SSB enough so that he didn't suffer massive diminishing returns if he uses it too often in a short period of time) because he basically wanted to show it off to the Universe 6 Saiyajin because his paternal instincts flared up. Fortunately, the stakes for that tournament were relatively tiny since losing would only have resulted in Earth being transported to Universe 6, which seems to be more or less identical to their own Universe 7 from the perspective of a planet who is not already part of their local Galactic community.