I've done this before.
Sometimes you just need a break from people for whatever reason, I like to listen to music or read during my breaks to relax and enjoy a bit of time to myself.
I remember one guy I used to work with who would talk constantly, if he spotted you in the canteen he'd be over and sit down uninvited and immediately begin chuntering on about football. It didn't matter if you responded or not, it didn't matter if you liked or had any interest in the sport, I'm pretty sure he just loved the sound of his own voice. I have absolutely zero interest in said sport and he seriously got on my nerves, wasn't really the type you could talk too either as he'd went in the huff with people in the past (without taking the hint) when they'd asked to be left alone.
I go to work to work, and while I'll be polite and friendly within reason I'm not there for a social life. I might make some good friends, but I don't necessarily want to spend all my time talking to colleagues, some of them like the above example just get on your wick.