Loose lips. People who think they're comedians, who say stupid or ugly things without even thinking. Around here they're most likely racist and sexist, but the holiest of the holy nationalists who often talk of the wonders of anarchy without actually understanding what it means. . . and they fanwank to zombie or slasher fiction.
Having a go at people on here then getting arsey when they get some back
Being conservative, being a racist, doing the same thing over and over again even when it is obviously wrong, knowing the facts and doing just the opposite of what you should.
Trying to do some thing good for evil people
Unplugging the freezer when it is full of meat and going on vacation. Oh, and marriage.
Being afraid to admit you may not know enough about something. The most stupid people are the ones who think they already know everything there is to know and they simply ignore or tune out anything that does not agree with what they already think.
If you are non-stupid, you realize that there is ALWAYS more to learn, and you're not afraid of being exposed to new info and ideas, even if what you hear may threaten your precious world view a little bit.
Parroting brain farts heard on Fox News.
doing first, thinking later. Or never.