We all like to think we are not prejudiced, but I will happily confess to a few little prejudices. Mind you a prejudice is supposed to be an unreasonable opinion and, like all prejudiced people, I think these are perfectly reasonable and they save time.
The first regards outward appearance. I know you should not make snap judgements based on appearances but when I see somebody wearing a Bluetooth headset permanently they are going to have to work ten times harder than anybody else to make me take them seriously.
The next one is a useful filter for comments on the internet. Sometimes you see a comment thread on a bulletin board, or on a newspaper article or on a Facebook post that is so big you just can’t read all of them so a handy rule of thumb is to ignore any comment that contains the words “should of”, “could of”, “must of” or similar. I am not sufficiently competent in all aspect of the language to be a grammar nazi, but that doesn’t mean I have no standards at all.
Another litmus test of whether to listen to somebody’s argument is if the phrase “we are only a small island” is used. It is OK if the person is referring to Rockall, Scarp, Canvey, or even Malta or Tuvalu but if they are referring to Britain I have to restrain myself from ranting that we are not *a* small island, we are a collection of islands, the largest of which is the 9th largest island in the world. I bet I would feel even worse if I lived in Northern Ireland.