Rejecting people sucks. I haven't done it very often, most of the time if I've gone out with someone and had no chemistry, it's pretty apparent on both sides. I've been dumped a few times and been the dumper I think exactly once.
Anyway, I went out with a fellow from OKC last Sunday who was perfectly nice, but just not what I'm looking for. No real attraction, our conversation didn't flow very well, and it just didn't seem like we had a whole lot in common. He's now emailed me twice, asking for a second date. The first time, I honestly just got busy during the week and forgot to respond, so he sent me another message today asking me out again, and wanting to know if I had a bad time since I hadn't responded to the initial message.
Leaning on my efforts to be more firm and concise, I wrote him back and said no thank you, that I had a pleasant time but did not feel a connection between us. Guh. It feels weird. I want to do the right thing, though. No apologizing for it. No ghosting out and just not saying anything like an asshole, after he went to the effort to make a straightforward attempt to ask me out again.
I'm an adult. I will behave as though I have (metaphorical) balls (of integrity) and not default into playing the nice guy.