Dangerous to the people who would impulsively choose to be euthanized?

Canada has a 90-day assessment/waiting period for those whose deaths are not reasonably foreseeable. They won't euthanize you unless you seem capable of making the decision and have thought through it for an extended length of time. It's not an impulsive thing.

And yet, "Within a month, Nichols submitted a request to be euthanized and he was killed" which is pretty quick considering median waiting time of 25.6 weeks between referral from a general practitioner and receipt of treatment[1]

[1]https://www.fraserinstitute.org/studies/waiting-your-turn-wa...

But, isn’t it their choice? If they are adults, and have lived at least a few decades..

I’ve never figured out why we as a society want to impose our morality on others.

I find this statement a bit too generic. Should society allow everything happening between consenting adults?

Between "consenting" adults that doesn't involve anyone else, absolutely..

Could you give an example when it shouldn't be allowed. It's certainly possible I'm not considering everything.

There was this case a while ago of a wannabe cannibal who found someone who wanted to be eaten. The cannibal was arrested. Are you saying he shouldn't have been and it was perfectly fine for him to eat a consenting adult?

And admittedly I'm reaching right away for the edgiest of edge cases.

Edit to add the link: https://en.m.wikipedia.org/wiki/Armin_Meiwes

Shouldn't it?