Got to be mmmmmmmm for me. Argggggghhhh became a little tiresome for me (and Mr Popkins) during the second half at Crawley. There's always a good time for an mmmmmmmm.
Mr Popkins, I suspect, will say both are very immature.
Last year, at the first time the opposition goes "oooooooh" when a shot goes close, the East stand at the Madejski dances around, and does a countdown of "10-9-8-7-6-5-4-3-2-1 ooooooooooooooooh".
Works a treat at the beginning of the game! Then loses its appeal after two or three countdowns. We tried 20 to 1 once, got bored after about 15!