I've often posted that I'm a bad B/X GM.
In the comments to
this post, Luke Crane describes GMing Moldvay Basic as
a hard game to run. Not because of prep or rules mastery, but because of the role of the GM as impartial conveyer of really bad news. Since the exploration side of the game is cross between Telephone and Pictionary, I must sit impassive as the players make bad decisions. I want them to win. I want them to solve the puzzles, but if I interfere, I render the whole exercise pointless.
I suck at impassive non-interference. When I'm GMing, I'm constantly reminding my players of what is (or might be) at stake, asking them how such-and-such relates to so-and-so's convicition about such-and-such-else, teasing and taunting them, discussing how certain moves might be made or resolved, etc.