So would you have ASKED for a drink of water if the only other adult in the room happened to be the Headteacher?? I think the answer to that question is fairly obvious! I do believe you probably would get a drink for the TA if she had asked you, but my point is that she wouldn't! My "problem" is that you seem to think that an experienced member of staff is there to serve you, when in fact her time is there for the children. "TA" stands for "TEACHING assistant", not "TEACHER'S assistant". You're an adult, get organised and carry a bottle of water for goodness sake, and let the TA get on with supporting the children! I totally agree with helping other people, but not in demeaning others because you happen to be half a rung up the school hierarchy ahead of them.