Acronym meaning "Write a Fucking Email". Often the action part of a remark that may be uttered by a person who becomes increasingly bored or annoyed while hearing someone complain about how they've been "wronged" by or displeased with someone or something, typically a co-worker, or a company they do business with.
In many instances, it serves the same effect as telling you to STFU and send a written complaint to someone who cares or can actually do something about it.
In other cases, it can simply be slang used in giving someone advice on how to handle a problem where they feel "slighted".
Elwood - Damn! I hate that electronics store! That place is a mess and you can't get anybody to help you find anything, and when you do their clerks are retards! The store reeks like a locker room. And, not only that...
Martha - Whoa! Dude...! Chill! Why don't you quit griping a W.A.F.E. 'em...? Ain't nothing I can do about it...!
* * *
Travis - Man, I am so tired of marketing sending me layout changes after the deadline. Three weeks in a row now they've caused me to work late and miss Happy Hour!
Eddy - They're gonna keep on doing that stuff to you until you WAFE those losers. Copy their Manager and tell them you gonna refuse anything they turn in past the deadline.