We have a #world-is-on-fire that's only meant for doomsday-like events
e.g. the API servers are down, slow queries exploded or a deploy resulted in 10 fold exceptions. Pingdom and Datadog triggers post to it, so if you see the channel name in bold, you'll know you need to drop everything you have and start panicking.
I know of a company that has a "#sbrocco" channel suited to unleash your rage and just let it out.