When I direct a sim to go use the bathtub they go to the bathtub, then stand there for 3-4 hours (game time) before actually using it. I know sims getting stuck is nothing new, and I have seen threads about getting stuck in walls, chairs, hot tubs, and IN the bathtub, but not get stuck standing by it like they are contemplating if they should use it.

Sounds like a standard issue that the game sometimes has switching between outfits. Does it happen before they take their cloths off? Either way next time you notice your sim freezing like that try pausing the game for about thirty seconds real time.

It happens before they switch out of their clothes.

Then yeah it sounds like it's just trying to remember what your sim looks like naked 30 seconds to a minute of a real time pause should save you hours of sim time waiting for the outfit to switch.

I've had Sims be late for work and school because of this.

Yeah that is my main issue. I will try pausing it next time, but that would be annoying if I need to do it every time.

If you've got NRaas MasterController, you can make Sims change outfits without having to spin into them. I can't quite remember exactly where in the menu it is, but selecting it changes their clothes immediately without any hassle. Frustrating to have to babysit your Sims to make sure they're getting dressed on time, but it's better than having to pause constantly, imho.