Common scenario (HU pot).
You raise with 44.
They shove.
You call?
They shove.
You have 44.
You call?
They were the two most common situations I could grab off the top of my head. You are flipping, at best, with 4s. Yeah, you're probably ahead preflop, maybe he has QJ... by the river that could be a different story.
I'm not advocating you NEVER call with 4s, obv each situation is read/player/chip size dependant. God knows I love shoving them from the BB
I'm just saying in those two situations, I would fold them a large majority of the time (unless I was getting a good price).