Over your carreer you will find that snickering such as that is usually a sign of fear as well as disrespect, and quite unhealthy. You might benefit by taking a step back and quietly take in what you need and put the rest away; the later is still in your recollection if you should need it later. Get your post-graduate work behind you, then run over the snickerers like a steamroller.
I've a lot to say about criticism but will reserve it for a separate thread, possibly some time when I am on vacation and have time.
May I ask what school you attend?
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