Now you may think this has nothing to do with jobs, but I was surprised on my last position to be confronted with that exact situation. What did I do? I reverted to my 13 year old self...and cried.
Instead of standing up for myself and telling this bully to lay off, I resorted to telling my husband and others in the workplace that I hated the guy, avoided him at all costs and when that wasn't possible humming an annoying repetitive tune in his presence. My inner child was awakened and was obviously going to be up all night.
Of course none of this resolved the problem, because the problem was that I was now the 13 yr old who didn't think they were good enough. The adult - the one who had raised independent children, wrote legislation, owned and managed businesses had to my surprise quickly retreated in the face of unfounded criticism. Yes, I logically knew that the job I was doing was excellent and the bullying had more to do with him, than me. But it made me hurt and angry when he said things that made me think I wasn't doing my job to his standards.
Fortunately things were worked out and I came to my senses and we ended up getting along well, but one of the things that I want to warn those of you getting seasonal positions, is that there is normally someone working there on a permanent basis and you may look like an intruder to them. Particularly if you have a different or better or easier way to do the job. They may be defensive, derisive or ignore you completely - and THAT'S OK. Because you are going to move on - but they are not.
Let me tell you right now. YOU are good enough. You are not on a dead end career path, you are on a temporary rest area on your life highway. You don't have to be a superstar, or thin, or pretty, or stylish, or any of the things that the TV tells you. You are fine the way you are. Have as much fun as you can every day and don't let anyone make you feel small. You Are Good Enough.