Getting back to the subject at hand, sex without a feeling of obligation afterwards is probably my main reason. You both know you're there for a reason and both of you can get on with your lives afterwards. I've had a few one night stands with women I've met in bars and invariably I feel guilty when I don't want to see them anymore but they want to see me. The pooning way, nobody gets hurt. That's probably why I find it a little addictive for me also. The only one I have to blame though, is myself.
By the way, to all of you guys who feel guilty paying a girl for sex, I suggest you think of it this way. She's doing this for her own reasons and would be there whether you were a client of hers or not. At least with you being the client, it's you and not some bastard. When I see these ladies, I'm always nice and never get mean or abusive. I take care of myself, make sure I'm clean, and never go in if I have a cold or could make her sick in some way. She always gets paid the negotiated price no matter what kind of time I've had. I don't try haggling and I don't whine afterwards if something didn't meet my expectations. I just don't return if she wasn't my cup of tea.
Enjoy yourselves out there guys. Don't sweat the small stuff.