The continual ramblings on the PA system gets me as well, half the time you can't understand what the hell they're saying anyway, laughable when they say "make some noise Brisbane".When it was done by the British & Irish Lions crowd back in 2001 it was beautifully spine-tingling and intimidating. Now the crowd has no patience and wants to repeat the "LIIIIIIIOOOONS" part every second so that it's not drawn out at all. Loses it's effect. This is why people can't have nice things.
One of my favourites was the "What about... He's alright?" that got up at one stage. Probably stopped being effective when the Gabba started injecting 90db whenever they had the chance.