I’m not trying to be arrogant (it wasn’t through my merits that I was in this situation, rather it’s because I’m a male) but I always had a large selection of potential dates, including many who “already agreed to go out and is just waiting to hear a ‘yes'”.
Nevertheless, there was still some pain in being rejected- even if I asked for it by trying to disprove Fermats Last Theorem on a first date.
Now look at it from the other side. Some girls have to wait weeks or even months to get a date. Imagine the hurt feelings of not giving them a second date. I still remember my sisters and their friends discussing how some of them “just couldn’t ever get to a second date”.
Isn’t it worth a few dollars and a couple of hours of your precious time to save another persons self esteem?
(I know most people will not agree with this, but I heard a story where a Rebbe suggested a shidduch to a Talmid and the Talmid wasn’t interested. The Rebbe asked him to go out with her anyway- just to boost her self esteem- since she hadn’t had a date in months.)