It may happen slowly, maybe gradually. But you open your eyes and now the person you used to jump out of your shoes for now makes you curl into a ball and go "Oh Jesus, not again."
You feel like a bitch. Maybe its you. You're overreacting and being mean. But just stop and accept it- it's okay. Say it.
Your best friend is fucking annoying.
Don't feel bad and realize it happens to all of us. It doesn't mean that your friendship is going to end. It means your growing, changing and adjusting. Friendships are like carseats, once you grow they get a little tight and you have to make accomodations so you can sit comfortably.
And sometimes, growing involves letting go of some friends and that's okay. Holding onto something only makes things worse.
Annoying friends are a part of life. Not everybody is as chill, excited, etc. as you are and that's perfectly fine! But why are they annoying you?
With my personal expereince, it was the lack of consideration and maturity. I am mature for my age because that is how I was raised, and my other best friends are the same way. Which is why others can be so annoying and irritating, because while we may be mature in our mindset, clashing with someone who is still 12 in their own life doesn't work. It's like mixing oil and water, you only get a disgusting looking bubble in the middle.
It's with these friendships you need to set boundaries, but you don't have to make them known. Just set them internally.
Don't have sleepovers... if you get annoyed. Don't go on vacation together... if you get annoyed. And the list varies for each person. Stick to lunch dates, movie dates, and little "hang-outs." Don't force yourself to do all these things knowing you will become angry and annoyed, because it only causes damage.
You know what's best for yourself- go with it.
I know better than to say "just tell them" and if you do... you have guts. Because I can't. But when it comes to consideration for your belongings, time, and money- something needs to be said. It doesn't have to be mean. Tell them simply "I wish you had more consideration for (insert object/thing here)" If they get mad, then they're not a true friend. If they understand, then leave it at that. You don't have to explain yourself.
And most of all, don't try and change them to somebody you want them to be. Because that's messed up and only turning the "inconsiderate and immature" card on yourself.
Take a breath and sit back, this is normal. Let it pass and learn from it.
People are annoying.