how established is the "doesn't remember faces" thing? We only saw it one time, when it really wasn't the same person, right (gai and fake Kisame). did it happen another time?

anyway, If we say that Gai and Kakashi are the same age group, Obito might have met Gai when they were younger. maybe he's furious at him for forgetting about Tobi (himself), like the rest of the village has.

I'm not going to argue the rest of the case for Obito=tobi. Partly because I've done it enough since Kakashi showed he 'learned' M.Sharingan. and partly because I care enough to post on Naruto forum, but not enough to go through the whole story again.