Without hurting someone's feelings?

A couple of hours ago I met a guy in a Little Chef (the restaurant chain - stop it). I chose it deliberately because I'm sure that no-one I know would ever go there. The idea was to chat in a public place prior to arranging a session in the coming weeks. I think we got along fine and there's certainly enough of a spark for me to want to take things further and will make an appointment for him to visit for some quite hard CP (his request) the week after next.

It set me wondering though; what if there's no spark? What if I thought 'ooh yuk, not on your nellie, mate.'? How do you tell someone who's keen that you're not keen on them? I know it's going to happen as we can't all get along with everyone so what should one say? It's also bound happen the other way about sometime and, hopefully they'll have the courage to say exactly what they mean.



Thoughts anyone?