I get a lot of that shit too! It sometimes goes to the extreme. There are people who assume I am 'gay' because I have been single for over 5 years now, focusing on my career and sorting my life out! :P
All my friends (pssht, "friends") are in relationships but me, and it's like they rub it in my face and even think they're better than me because of it. What they don't realize is that I don't give a shit, lol. I'll get in a relationship when *I* want to, and not a moment sooner, and not just because I want to fit in and "everybody else is doing it". It's just not worth the drama to me, college is hard enough
People will think that anything outside of their experience is weird, especially when it comes to something that some had to struggle to attain. Once you finally get it, you felt like you achieved something. But when you see someone who doesn't even want to struggle the same way you did, your brain starts thinking that they are lazy, or that you're superior to them for doing it while they are not. That or you got in to a relationship but judge others who haven't because you are insecure over the possibility that you have made the wrong choice and thus someone who actively avoids making the wrong choice seems bad to you because you don't want to be the only idiot - it's easier to be mistaken when others around you are mistaken as well.