Having played a lot of 5E, I would say that your impression and squeen's impression that 5E play is inconsequential (in the sense that it avoids having serious consequences) is spot-on. It's not that a DM *can't* present players with something like a machine that, if you place two limbs in its two holes, permanently switches them; and if you place only one limb in it, severs it. You can do that--but it feels un-idiomatic for 5E, because generally in 5E everything resets with a good night's sleep. (There are exceptions but they are haphazard.)
It can be *modified* to challenge or frustrate--imagine someone running a 5E variant where scaling a 30' wall takes climbing hooks, special shoes, and 10 minutes, instead of 6 seconds and a d20 roll. But why reinvent the wheel instead of playing a game with challenge and frustration built in?
