It ruined Finding Nemo for me.

"Aquaman"? No.

"Mission Impossible"? Yeah.

Depends entirely on how likely I think it is to be in any way realistic. Often I might check the time they're underwater. 1-2min is still realistic, although very challenging for an average non-trained person. You can quite quickly train yourself up to a few minutes, some dude on YT tried went from 30s to about 4min.

However it's usually reliant on conserving oxygen, having a low pulse and no adrenaline etc. Quite the opposite of what is usually going on in movies like MI.

No. Do you have sex during sex scenes?

Depends on the scene. In the one aliens movie (resurrection?) where they had to swim underwater to the next hatch, yes

Yes, but just until I realize I'm doing it then I breathe.

no

I'm sure that I have before when a character is oxygen-deprived, but I can't remember exactly when.

I think I did when watching that scene in Event Horizon where a character is momentarily possessed and enters an airlock and initiates the decompression sequence to space, where he's briefly exposed to a hard vacuum before being knocked back into the airlock by a rescuing crew member.

I did as a child.

I don't think I've ever done that but I do hate seeing deep cuts and bleeding in movies (and IRL as well) and the longer it goes the woozier I feel. I start getting pale and uncomfortable, lol.

Ya goddamn right I do.

I remember doing it a lot during a long kiss goodnight water torture scene.

I don't but it probably wouldn't ruin such scenes because I have always been a swimmer and can hold my breath for a fairly decent amount of time, almost 2 minutes.

The record without pre-gaming with oxygen seems to be about 4 and a half minutes.

I do this when playing video games.