Add me to the list of people who bristle when their integrity is questioned. Of course, if someone does so with the obvious express intent of angering me, it doesn't work, but otherwise I can tend to
react strongly.
Another thing that buries the needle at zero on my Patience-o-Meter is when someone gets pissed at me for something that was no fault of mine. I am all too willing to take responsibility when something
is my fault, but when it isn't, you won't find me willing to take abuse over it.
I used to be an extremely patient, calm person almost without exception, but my stress level hasn't been allowed to sink below the high mark for a long time, and it tends to make me a little easier to irritate. Not that I'm a raging asshole, it's just that now, when someone cuts in front of me in a line or talks in a movie theater, chances are I'll call them on it rather than just letting it go like I used to do.