Favorite scene in season one? Drunk scene where Kyle and Max are talking. Literally one of the best scenes in the entire series IMO.
Favorite scene is season two? During the Christmas episode when Isabel drops by Micheal's apartment to "drop" off the Christmas presents. The covo between the two is awesome.
ISABEL: What are you saying? That I get obsessed and make everyone around me miserable?
MICHAEL: I didn't say that.
ISABEL: You know, is it too much to ask that one day a year, I can be like a normal human being with a normal life and have a merry Christmas?!?
MICHAEL: No, mein fuhrer.

especially the like half smile/smirk Michael gives as soon as Isabel leaves. AHH MY FAVORITE MICHALE LOOK EVER.
Favorite scene in season three? Candy Cane and Santa fooling around in elf house.