Aye, creepers got a LOT more irritating ever since they merged sigle player and multiplayer. Used to be in SSP creepers would be fairly reliable. You could predict more or less exactly when they would explode and you could melee a creeper down fairly easily with a bit of practice. SMP was different, thanks to network lag creepers could explode whenever, or not explode when they should and it was nearly impossible to kill one in melee without getting exploded on because of this. And then Mojang merged SSP and SMP and now SSP creepers started being unreliable... and did that EVER irk me to no end. What used to be a well practiced maneuver was now reduced to blind luck thanks to network lag...in a single player game, what? Just WHAT?
They've since fixed their network code quite a bit, but the unpredictable lag has never quite gone all the way away. In a way, it makes creepers feel a bit more "organic", but I'm still a bit irked by it all.