Do ultimatums ever work?

If they do out of a helplessness or no other usable alternatives it festers resentment. So it will only work until some other solution presents itself.

I would think that would depend on a number of factors - the nature of the situation, the character of the person, the personality of the person making the ultimatum. I could go on...

not with me, I always reject them on principle. It's like when people ransom hostages: if you pay the ransom then the kidnappers see that the strategy works and will use it again.

Gets things done.

Depends on the situation.

Depends what you want to achieve. To me the most important thing about an ultimatum is having the ability and willingness to carry it out. If one of those two are missing..an ultimatum becomes an empty threat.

This is the last time they will work!!

Either the first time or else!

Nope, never.

It forces a decision to be made sometimes.

Its better than saying let just murder each other