There's a few technologies I actively try to avoid (.NET, etc.) but otherwise I'm open minded.
But I am much more peculiar on what kind of company environment and culture I want to work for. Call me trivial, but I really, really, don't want to work for any company that forces me to wear business casual (or worse). It's not just the dress code that irks me, but the wider culture it typically implies.
In fact, the reason I'm adverse to certain tech like .NET is also related to company type/culture that would use such tech, more so than the actual tech itself. I happen to like C#.