Yes.. that "Please don't hurt my friend" was the most touching and human moment Sheldon has ever shown and Jim Parsons delivered it perfectly.. a little awww escaped from me (good thing i was watching alone
).
As to Penny.. really getting fed up with her a bit. Luckily i read an interview with Chuck Lorre who basically said it follows a plan they're having namely that a big thing this season is the bad timing of Penny and Leonard and that Penny has a little bit of growing up to do.
For once i'd like to have Leonard dump her when (and if) he finds out.. he needs to man up a bit which coincidentally is maybe what Penny needs.. someone to stand up to her bullshit because honestly.. she'll most likely not find a guy this good amongst the usual idiots she favored previously.