Hitpael, Zivui, and Zivui Hitpael have ruined my life. I swear to DWEIQ, everyone in my class was so confused by it, I managed to convince half of them "Lehishtael" ("To cough") meant "to become a fox" (Because "Shael" is a fox).
And my teacher tells me all these Yotze'ei Dofen are because it's easier to say when you're whispering? Why the FUCK would you get into the finer points of grammar when you're hiding from the Gestapo!?