People are emotional and react in unexpected ways to even the smallest perceived slights, myself included.
A late birthday recognition might not feel important, but if one already feels like management doesn't care about them? I can easily seeing that as a confirmation of it that causes resentment. I can also see it doing the same for any number of management related issues.
I can tell you personally that the action which most seriously affected my performance at a workplace was being denied a bereavement day because the official policy was to only allow one. I felt more than slighted and every single negative action taken afterwards by HR/management, no matter how small, caused me to resent them more.
> being denied a bereavement day because the official policy was to only allow one
I think when setting up policy like this you have two choices:
a) have a fixed number of days --> fair, objective
b) allow it to the manager to use their judgement --> variance across company
The former has the tradeoff that you experienced.
it also depends on whether everyone is treated equally, or whether some are treated worse or better than others.
> I can tell you personally that the action which most seriously affected my performance at a workplace was being denied a bereavement day because the official policy was to only allow one.
One of the things I remember most from my career was a manager "rules lawyering" about bereavement leave when my aunt passed away. Ironically, HR was very sympathetic and accommodating, and it was a non-issue with them.
I've been treated "worse" by jackass execs and managers, but always in the context of work. Someone acting in the way this manager did about a personal situation sticks with me much more than those.