I do have different platonic female friends, or varying "closeness", including one who's like one of my best friends. With more casual female friends I find it's important to keep some form of a distance (unless they're single and somewhat attractive then usually obviously I don't care about keeping them as friends, there can be mitigating circumstances though). For example a female friend that I get on with well, I know I could talk to her a lot but I try and chill on this, if texting it'll only be for specific things we've discussed or maybe upcoming plans, never just a general random texting session about nothing. I've had it where we end up texting back and forth for like a whole evening, and then it's like, this is similar to how I'd text someone I'm seeing? Is this crossing a line to that sort of territory?
And that grey area is not nice actually. I think everyone apart from gigaChad has been friendzoned at least once in their life, and it's a confusing and unsettling feeling, definitely even worse than an outright rejection. It's because it's just a lingering doubt that you have no clarity on, and making that move outside of the "friendship" you have is just so cringe, and you're becoming aware "damn, she probably finds it hilarious we've just been chatting casually about nothing and now she knows in my mind it was all leading up to something, when it isn't".
Well, that's the circumstance I think a lot of guys on here can relate to, the other "circumstance" is when she has a boyfriend, or something like you've been with one of her friends before, or she's been with one of yours, a huge age gap, or just something that makes it wrong.
With that, developing sexual tension is pretty awful too (not as awful as the friendzone however) and you find yourselves un-intentionally flirting, stealing looks at each other, and it's exciting in a way but also kinda gut-wrenching because nothing's actually happening and you feel a bit stupid getting all giddy about it. You can sort of tell she's feeling the same way, it just feels so childish but you can't help it.