Something that really upsets me about palaeoartists who draw extinct mammals in particular is the rampant shrinkwrapping.

Compare a hippo skull and hippo head:

Or a pig:

And now look at how extinct mammals are depicted. Like entelodonts:

Or uintatheres:

It just……really doesn’t follow what we know about mammals, at all. I’d wager both entelodonts and uintatheres had a LOT of soft tissue on their heads completely obscuring the shape of their skulls, and so did a lot of other extinct mammals.