Administrators worry - a lot - about undoing each other's actions. It's known as wheel warring and it drives someone crazy.
For the record: it doesn't bother me. Well, it does when people do it to each other. I mean, it doesn't bother me if other admins wish to undo me. I'm not perfect, have never claimed to be and can't see a Wikipedia rule requiring it!
- Disagree with the delete I just did? Undelete it.
- Disagree with the block I just did? Unblock.
- Disagree with the protection I just did? Unprotect.
It's not wheel-warring, it's just common sense. Feel free to drop me a line (not to explain, just to tell me you've done it) but only if you want to.
The only time I think I'd get peeved is if I was closing an AfD or the like and you didn't agree with my decision and undid it. But even then, I'd likely turn up and talk to you about it rather than stamping my foot or undoing you.