If you have to strain yourself to be nice, you are probably not being nice.
Most women, when asked about red flags they've learned to avoid, will be pretty straight-up about telling you that they almost always run when they hear about men who describe themselves as "nice guys." Though we're sure that there are some guys out there who are nice and describe themselves as such, the sad truth is that they're few and far between.
The internet's "Nice Guy" memes show how often guys believe they should be rewarded because they didn't treat someone heinously right off the bat. Even in "normal" conversations on Tinder, it's easy enough to run into guys who think they're entitled to sex or a meet-up just because they were polite to you. Then, they flip out when things don't turn out that way, and their real faces are shown.
Obviously, people who see the world this way aren't actually nice — they're psychos who don't understand the way the world works.
Here's what too many people don't understand about the meaning of "nice." Nice doesn't mean just being polite. It doesn't mean that you do things in hope that other things will happen. In the real world, nice means actually doing things because they're the right thing to do. It means doing things out of the kindness of your heart, and it also means that you don't expect something extra in return. Nice means being a decent person.
If you have to force yourself, or even actually strain yourself to be nice, you are probably not being nice. At the very best, if it takes such effort to be nice, you're probably only being polite. And chances are that you're being polite in hopes of something in return — and that's being manipulative rather than being nice. Sadly, it takes more than "nice" to get a girlfriend or a boyfriend.
If you want to actually function among people, you have to be polite. Otherwise, you end up getting into fights, hurting innocent people, and having everyone avoid you. Polite alone is not enough to make you nice, though, and people pick up on it.
When people realize you have ulterior motives, they will back away. They don't want to be used. And that keeps you away from actually making a connection half the time.
Since so many people don't really understand the difference between nice and polite, and since so many people don't understand that nice doesn't necessarily mean you'll get a partner, it's understandable why Nice Guys feel the way they do. They honestly think they're truly nice, and they honestly feel like people don't pick up on that.
They try to show people that they're nice because they're hoping people will pick up on their "niceness" and decide to be around them. They really do believe that people are just not noticing the effort they made, and that they need to be rewarded for doing the bare minimum of being a decent human being. That's why their protest cry is, "But I'm so nice! Why won't you give me a chance?"
Here's the sad truth, though. If you feel like you have to remind people that you're a decent human being, chances are you're really not. And if people notice that you feel the need to remind others of your niceness, they also might pick up on the fact that it's a niceness that comes with strings attached. And that makes you a jerk.