I'm amazed at how many coaches carry out games in utter silence, saying nothing more than "gl&hf", "grats", "thx" and occasionally maybe a "gg". Unless you got a real good reason for not touching your keyboard (like someone in your familiy is a devotee of Nurgle) I can't see why such a lot of coaches simply say nothing during a game. Would they do the same if we were sitting in front of each other playing a real life BB? I think i would like to see my post here as a wake-up call to the mute ones. I personally get much more from a game if there is some joking, taunting and maybe even cursing each others luck involved. Interesting enough, most of my opponents didn't complain when I fouled their starplayer to mush after telling something along the line "Now your <insert player here> really has to die. My boots got his name on em!". Usually the opposite was the cause, instead of a "you fouling #@ç5**" I mostly got some funny/amused reply in return. I myself am even able to enjoy a foul against my players if the talk around this is funny enough.
IMHO the same counts for all of the often-discussed tactics to "abuse" the game. When you're stalling, tell your opponent what a slow bunch of slugs his team is made of. Fouling? Of course, but wrap it up in some kind of reasoning, even if it's "I like this *kersplush* sound soooooo much". Yell "GROUPHUG!" before crowdsurfing my ballcarrier. After your AG5 catcher dodged through all my players and scored drop a "that was easy!" or something. I think all these things make the game more fun, even if a lot of things aren't really funny or creative. And if you're the humorless type, just comment on tactics, moves and stuff. Just keep the chat rolling!