Hey there,
Whenever I end up in a wonky match, I usually do stick it out anyways for the credits/cxp/Valor stuff at the end. Lopsided matches can be quick cxp if I at least tried stuff and nabbed a few medals.
I don't think too much about "egos" or how I look because when looking at the whole picture, the whole team isn't working out that great (whether that means the other team is doing very well or my team just isn't). Sometimes surprise comebacks do happen, and sometimes they don't.
A general rule of thumb I use for myself is that I'm only going to pvp- well play any game- so long as I'm having fun with it. If I enter a match and realize I actually don't want to be here, I leave and take a break. Don't feel compelled to stay in a match if you're really not having fun in game. I've found that I don't do so well when I'm entering a game feeling tilted for whatever reason that day. Might be better to just chill with something else.