To all the friends that define my life: I'm so grateful.
We love a friendship moment. Community. Nostalgia. Fun times and distractions.
That said, there are lots of types of 'friends'. Some are better than others, some you only gossip to, others you exclusively eat with. But beware of the fake friend. Or the 'yes man' that doesn't challenge you and lets you make mistakes. They don't offer you anything and can often be unconsciously manipulating you. Try to take a step back and recognize these types of friends from each other. You deserve the best, after all.
We all need that 'I am not okay' safe space friend. Having your mum or dad or sister on speed dial is one thing. Having your old primary school best friend across the world might not cut it anymore. But your person – some version of a platonic soul mate maybe – needs to be there to recognize and truly see you. To listen to you and actually hear what you're saying. Who counts down the days to your birthday so that they can give you really thoughtful presents and a card that will make you cry.
These friends will be around forever and will be the same for you now and in the future. You might as well send them the maid of honor request now because it's on lock.

However, some friends aren't really friends anymore. It's tough to admit it, but we all have to recognize that people change. We're allowed to! Obviously! But that recognition comes with the reality that you have to move on from people that you aren't compatible with anymore. Maybe their confused jealousy from when you were younger has expanded into manipulative tendencies. If they can't stand to see you succeed, they might try to let you fail. Beware.
That said, just because you aren't as similar anymore, doesn't mean that you shouldn't be friends. Use your gut instinct.
Moreover, it's the old saying – opposites attract. This is true of lovers and this is true of friendships too. Sometimes you need a healthy amount of distance and difference to keep things interesting and to stop you both from merging into each other. That's no use to anyone! Ideally, you would have the perfect blend of a headstrong and impulsive individual with a more reserved, careful character – with various other attributes in between – so that you can learn to let loose with each other and be goofy, while also being able to plan trips and have a response time. Get yourself a best friend that can do both!
Nothing is as important as a good friendship. A truthful friendship.
A friendship with secrets does not make a close relationship. Just because you confide in each other in petty matters of gossip doesn't mean that you actually trust each other. Maybe you don't even have any emotions invested in them, but you often don't realize how toxic they are until you step away. So try to get some perspective when you can.
One of my closest friends surprised me the other day for my birthday when her mother was revealed to have sent up a card as well as her own present.
I was closer to tears, no word of a lie

As such, the only thing that can truly rival this feeling is in the initial confirmation that you and your best friend are in fact, best friends. Oh yes, there comes a point in any good relationship worth its salt that you have … the talk. Who are we? What are we to each other? Commitment?
At the end of the day, your best friend is your best friend for reasons that probably don't compute in any sort of algorithm or checklist. They are simply always there for you and put your interests above anyone else. You call them when you have news because they are frankly the only person who knows that you were expecting news in the first place. They're always on your mind – be it in the form of a funny text, a joke that they would have enjoyed, or a meme that you just have to show them.
They will make you feel better than you thought you were capable of feeling.
If they don't do that, they aren't your friends. Simple as.
They should challenge you, tell you when you're wrong, and support you through your mistakes.
If they don't want you to succeed, then how can they possibly care about you.
Answer: they don't. Move on from them in the future.