I imagine that we've all been nasty from time to time, some of us more than others. What causes this unpleasantry?
I can think of lots of reasons including the following:
- you're overwhelmed
- don't have time for what someone else wants to say, do, or advocate for
- you weren't well schooled in good manners
- you don't feel good
- you feel unheard
- you're oppressed
It's good to be cognizant of when "nasty" arises and then to think about where that began and how to mitigate it as much as possible.
The best cure for nasty is when someone is nasty to you--that reminds you of just how unpleasant nastiness is.