"If you find that you're doing a lot more eye-rolling than high-fiving these days, your perception of them might be changing, and not necessarily for the better."
You feel like you don't know the person in front of you. When you first met them, you were so in sync, that you could practically read each other's minds and were almost always on the same page. Now, when you guys talk, you get into little non-arguments. You know, the kind where you aren't exactly fighting, but you fervently disagree with almost everything coming out of their mouth. Try as you might, you can't relate to them - or worse- you don't get them at all anymore.
You don't feel a strong drive to reach out. If you do reach out, it's mostly out of guilt or a feeling of obligation, and not a genuine desire to reconnect. It's not that you necessarily abhor speaking to them, but it's one of those things where you could see/hear from them... or not... and it doesn't make as much of a difference to you anymore. As b*tchy as it might sound, you just don't miss them.
Interactions that used to come naturally now feel awkward and forced. Whether you want to admit it or not, you guys just aren't in the same place anymore. Your old inside jokes are no longer funny. You may have become more selective about what you tell her (perhaps, without even realizing it). They are no longer the person you run to tell whenever something major happens in your life. And, as a result, conversations have become stilted and boring, and don't leave you feeling as connected to the person as you used to feel.
You find yourself being more judgmental of them. Now, I'm not saying that it's nice to scoff at your friends - it's not. But, let's be real - our friends do stupid ish sometimes, and we aren't always going to approve of every choice they make. But, if you find that you're doing a lot more eye-rolling than high-fiving these days, it could be a sign that your perception of them is changing, and not necessarily for the better.
When you ask yourself why you are friends with them, you begin with, "Well, we've been friends for x amount of years..." That should be the icing on the cake, not the main reason. Longevity is important. But, the quality of the time spent in each other's company is more important. If you don't enjoy each other's company, you don't have a friendship. So, if you have trouble coming up with other reasons as to why you're friends with someone, you might have some reevaluating to do.