Btw on the being corrected by a beginner thing, if the guy has been there long enough to at least know some things, like a few months, always listen. I think it was one of the Gracies that said "Always keep a white belt's mentality" I know how annoying it can be to listen to every white belt think he's come up with something never seen before, but you have to keep an open mind and being willing to learn from anyone. All though I can't say I'm not guilty of wanting to slap white belts in the face from time to time because they think they are correcting/showing me but it's important to at least try to listen.
Personally what drives me insane is whenever a guy comes in that's been grappling for a week and I show him a triangle, without fail he will always say "you didn't pull on my head." I swear to god it's happened at least 20 times in my jitz career, the guy comes to class for a week and tells me how to finish one of my highest percentage subs and he wants to correct me or tell me I'm doing it wrong.
Think. It Ain't Illegal Yet
"Discipline Hurts Less Than Regret"