But remember the Troll-in-the-Loo incident? After the action was over, I stood there and lied to McGonagall, and got away with it---even though the truth wouldn't have hurt anything. That was a test---and I found that I could get away with lying to McGonagall. Not that I do it very often; I make it my business to keep her happy with me, since she's so very useful. Besides, although I hadn't really planned it that way, the Troll-in-the-Loo incident also got me something I needed desperately---allies.