I recently was trying to convince a friend who has been looking for a job that it's OK to interview for a job that you might get offered, even if it's almost a certainty that you wouldn't take the job if you did get the offer. My rationale being that it's not at all expected that you'll take it, or that the job is a perfect fit, but that shouldn't stop you from finding out more about the job in the process.
Of course, being the philosophical muser that I am, I immediately apply this same line of reasoning to dating, and think it's complete and utter bullshit. Admittedly, the two situations are far from identical, and in the dating world you have a lot more personal feelings to be concerned about. But on the other hand, isn't that what dating is all about?
If you knew the person you were dating was the perfect person, there wouldn't be a point in dating... you could just skip right ahead to the rest of your life and happily ever after, knowing confidently that it would work out forever. Reality of course states that it's never that simple.
I think part of my problem is that I'm scarred from past relationships, and the overwhelmingly common situation of me having to be the heartbreaker rather than the heartbroken. It's so much easier to give up early on, before things get too serious, than later on when stronger feelings are at stake. But as a result, I almost have this innate fear of being put in that situation, so I shy away from relationships that could potentially work out really well.
I still wouldn't date someone knowing it wasn't going to work out... but I need to get over giving up just because I'm unsure... because who isn't?