It depends on the situation, the problem, the DM, the group and my buddy.
Firstly, the general procedures should be part of the dive briefing. That said, there are sometimes occasions where the pre-planned dive gets thumbed. Those are two very different scenarios.
Being told to ascend - in line with the dive plan, is one thing. Prematurely ending a planned dive is another.
I tend to be the one leading dives, so I don't often encounter being 'told' to end a dive prematurely. When a customer indicates they want to ascend, I'll always check why - because sometimes it is a resolvable problem that they don't understand. If it isn't a resolvable problem, or I can't understand what the problem is, then there's no issue or hesitation with aborting.
How the abort is managed depends on the circumstances. Some of the sites where I lead divers require specialist local knowledge - so I don't favour leaving buddy teams behind. As the dive guide, I am there to provide educated judgement for the customers. Ultimately, it's the customers call though.. if they are in a buddy team and want to ascend separately. Unless there is real (un-anticipated) danger, then I see no problem letting a buddy team continue the dive and/or ascend without me. I'll make a judgement call on which buddy team to accompany - those ascending, or those remaining.
I never dive with more than 2 buddy teams. If I have 3 divers, then I consider myself a member of a buddy team.
I don't see a problem with re-organising buddy teams 'on the fly', if someone needs to ascend, but their nominated buddy want to remain... especially when you can match divers with roughly equal gas consumptions.
In the rare occasions why I am a customer, with another DM leading, then I'll follow their directions. If I have cause to doubt their decision making, then it's an issue I'll raise post-dive with either the DM, or the dive operation manager.
For technical and wreck penetration dives, no question, no hesitation, ever.