I always liked the shout if one of the opposition defenders was a bit of a short arse when they were defending a corner and waiting for the kick to be taken...
"watch out for that no.3 - he is standing in a hole".
Or if a player is feigning injury and the physio runs on, then when the physio is walking back round the pitch after treatment:
"Hey, what are you doing at a tinpot club like this? 30 seconds ago that player was at death's door and now you've cured him. Bloody miracle worker you are."