I tend to get annoyed and impatient easily, and people just LOVE going on and on about themselves and other things that typically don't matter, so I do snap occasionally. I also tend to irrationally think that people dislike me, so I can be defensive or cold shouldered.
Depends on who you are. If I like you I treat you well, if I dont im either an ass to you if you continually approach/bother me, or im just indifferent.
Naturally nice in real life. People 99% of time return a smile too
It does wonders, I get passes for that sometimes. There is literally 0 advantage of being mean.