Should we generalize about people?

After reading the article "Should we generalize about people?" by Joel Charon, it made me understand the difference more between generalizing and stereotyping.  There was one part that stands out clearly to me, and that was when it talked about how we get our generalizations from the past and whatever we have heard, no matter what, we stick with it.  The example was the common cold, and how it's contagious and if you don't want to get it then you don't touch that person.  Everyone just "knows" that.  The difference between that and stereotypes, is stereotyping is on a specific group or person, so for example, if someone wears all black then they are weird, which isn't true at all. People stereotype without even realizing it too.  During this past summer I was a camp counselor, and all the staff seemed to talk to each other about the different "cliques" or "groups" at the camp.  For instance there were the college counselors, the high school counselors, the junior counselors, the counselors from the one unit that wasn't "cool", the specials staff, office staff, and the pool staff.  Everyone would always get ideas about the different people without even knowing who the were.  Why would they do that?  People use what they are thinking as a way to show more knowledge in one situation to the next.  So doing the "Short Sleeves" and "Long Sleeves' activity helped me understand that after being split up into my own group, immediately ideas were going through my head as to why the other group was wearing short sleeves without even asking.