In my early days on this forum I was far more combative. Those were the days before we had moderators. Great days. Lots of fun. Now, I'm a kinder, gentler PatrickHenry. Anyway, when breaking off the conversation -- something you must do! -- you could always announce your reason if it makes you feel better: "Well, if you're going to say X, then I can see there's no reason to continue, so I'm dropping out of our debate." But your opponent will almost always respond with some lame claim to victory. That used to bother me, but I now see how utterly predictable it is, so I just let it go. It's fine with me if he wants to tell his buddies about the time he "defeated" some "Darwinist" on the internet.