My old band went through many iterations before I found it all somewhat exasperating and jumped. Reckon we may have got up to A (me, obvs), D (second drummer), H (third guitarist) and L (third singer) before things really hit the fan.
L decided he didn't think D was any good and argued that we should try out ¥ (a drummer we all knew), to prove a point. So we did, but ¥ wasn't remotely interested in joining, but L thought ¥ would. A knew ¥ wouldn't. A knew D was a bit crap and H was on the fence, but L decided D needed to go and said A needed to tell him.
So A told him. It was horrible for A. A then found a new drummer through Facebook (let's call him P) and he was a great player, although Ps raison d'etre was primarily for shagging audience members even while his wife was there. 'Where's P,' she'd say, 'Have you seen him?'
L started to make life difficult for A, despite A writing the bulk of the material, and A left, eventually being replaced by Q, R and S, before the band imploded.