It's not him; it's you.
You go out on a date and have a really great time. The guy is funny, charming, and kind. You really like him. You both agree to see each other again and he says he'll call you.
A day goes by, and then two days, and then three, and he hasn't called.
Slowly at first, and then all at once, you freak out.
Anxiety. Frustration. Downward Spiral. Hyper-analysis of every single detail of the date, scanning for places where you might've said or done something that would make him change his mind. You begin examining every inch of yourself in the mirror looking for flaws he might've seen that you weren't aware of - blackheads, rogue hairs, love handles, cellulite. Eventually, you send him an awkward but nonchalant text message asking him how he's doing.
His response is distant, which sends you spinning even further out. You don't understand how he could shift so dramatically in the span of four days.
You are the one who shifted so dramatically in the span of four days, not him. Whether he's aware of it or not, he feels you, because you are connected, and when he thinks about you, and especially when he talks to you, he experiences (with no explanation, mind you) the same things you do: anxiety, frustration, downward spiral, neurosis, criticism.
If he's a fairly unconscious person, he will instinctively associate these sensations with you, and potentially think your self-criticism is actually directed at him. If he's a relatively conscious person, he may attempt to take responsibility for some of it - perhaps the part where he didn't follow through on an agreement - but ultimately, he will probably associate these sensations with you, knowing it has nothing to do with him.
Either way, the chances of another date are unlikely.
Whether we are conscious of it or not, we are connected to and can feel one another.
Why is this important?
Because what this means is that our way of being can be felt by those we are connected to, whether or not we are standing right in front of them.
This is why everyone is always talking about how you have to love yourself first before you'll find someone else who'll love you. Because lack of self-love is really loud even if it's not even remotely visible in physical or verbal presentation.
This principal applies literally everywhere.
If you're desperate for sex and think it's hard to get, that's all she's going to feel, and she's going to associate you with desperation and feel like you have an agenda with her (which will in turn make her not want to have sex with you).
If your business practice is a total mess and you lack any semblance of structure or ethics, no amount of pulling your shit together for a networking opportunity is going to matter to prospective clients. Ultimately, they won't trust you, even if they can't quite pinpoint why.
This all comes down to integrity.
How you BE in the world, even when you can't be seen, is how people will experience you.