I mean I kind of enjoy the "shockingly strong for his size" trope. And sometimes it's not too far from realistic. I have a couple of naturally muscular guy friends who are shorter than me, but who can lift me pretty damn easily, even though I'm only maybe 30 pounds lighter than they are.

But there are definitely limits to believability. If the liftee is already slightly smaller than the lifer in canon, and that size difference is commonly emphasized by fanon, then it's probably going to work for me in fic. But if you tell me that Tony lifts Steve, or Dean lifts Sam, or Stiles lifts Derek or something, then yeah, my brain is probably going to scoff incredulously.