<human>: They're a couple, and they do almost everything together, so that's why I refer to them as a pair. They even have the same first name, heh.

I haven't spoken to either them in a few months, because I graduated from college and moved towns (though I did write the usual "Happy Birthday/Happy Holiday"s note on their walls), but we used to hang out in the same crowd for most of last year and I was the lab partner of the girl in a class I took this summer. We had some good times together.

Now I just noticed that they both defriended me on Facebook, and I cannot for the life of me figure out what I've done...

I never, ever post offensive/controversial stuff on FB, in fact I rarely ever post at all, so I don't think it's because of anything I wrote. I don't ever post selfies or other annoying picture spam either.

I haven't seen or said anything to them in person in a long time, and I am very careful to be polite in any social situation. So we should be on good terms. I literally cannot think of ANYTHING bad or wrong I have said or done to them or anyone else in our social circle. So why would they randomly defriend me?

I talked to another friend about this and he said not to worry, that people just "clean up" their friends lists by removing people they haven't talked to on a long time. Personally, I never delete Facebook friends unless they've seriously wronged me, to the point where I wouldn't even speak to them IRL. I've only had to do that once, to the abusive boyfriend of my roommate.

Am I overreacting to this? I'm so worried that I've accidentally pissed them off, it's eating me up.

Can you provide a brief overview of the text?
<bot>: Two old friends randomly dropped me on Facebook with no explanation, and I don't know what I could have done to piss them off.