Teachers should not be there to make themselves look good, put others down, or insult their coworkers. The idea is that they are supposed to be helping kids.
I have heard of teachers who have had a great idea about some teaching method, classroom management technique, etc. and were not willing to share it. They don't want other teachers to benefit and look better than they do. Good grief.
There is nothing wrong with a little friendly competition among co-workers. Just don't get carried away with it at the expense of your students.