Crazy goes both ways. Sure, people overreact but typically when I am calling someone crazy I am engaging in behavior that irritates them.
Like, my mom hates going down the main street in my hometown because it scares her. It's totally irrational, especially when I am driving. But I know she is going to flip out and I have to ask myself is it worth her irrational reaction to save ten minutes? And aren't I equally crazy to even consider going down that street if it upsets her that much? Just because I don't scream or yell doesn't mean my actions are more mature.
If someone calls someone crazy because of an outburst, they should ask themselves are they doing something they know will hurt/upset/enrage that person. If they know what they are doing, well that just make them a psychopath.
Which I why I just don't drive down main street with my mom in the car.