@norawash,
Respect is not given to the subs who are so willing to stand and deliver. I have seen many poor sub role models, and then there is my peer group. We are professional, educated teachers or trainers or content experts. When you think of them as babysitters, you are so wrong and not using your sub resource very well. Of course, if a sub cannot teach a subject, they should not opt for that choice. It is a failure and report waiting to happen.
It takes years of subbing to get the following and respect.
However, it is very rude and condescending to be in a teacher's lounge and the social behavioral response to you is similar to having a disease on your face. No hello, welcome, thanks for being here, may I help you, how is it going. It is total indifference. Yes the sub is not of your "pack", but being kind is more than the slogans teachers post during "kindness" month.
Of course if they are talking to you it is to see if you can sub for them.