Hey you guys, sorry for the late reply. I truly appreciate all the feedback, I can find a lot of comfort in your words.
Ideally, I would want comments of the flavour "You should aspire to something better" to roll of my back, because yes I'm enjoying my current job very much-- and I find that I can combine my work well with pursuing my interest in my spare time. But I continue to be surprised at how many people seem to respond the way that they do.
As for my body language/tone when I mention my work, I've gone between the two extremes: sometimes, I am a bit humble about it and I say "Well, it's not the most flashy job in the world, but... etc.", or I make self-deprecating jokes about it. On the other extreme, I'll get highly defensive, emphasize that I enjoy it, and possibly add sarcastic comments aimed at the asker. Usually, I'm somewhere in the middle between those two extremes.
Not sure if I've mentioned this before, but I've noticed that when I attend events related to my interest in field biology, such as a botanical lecture day the other week, or an organized walk along the heath or forests, there is far less of this 'classism' involved. Virtually everyone I met there simply wants to talks about our shared common interest.
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clarity of thought before rashness of action