Once I go beyond a few dates, it's serious in my mind -- if I don't see the potential for something serious, I'll end it after a few dates, because I don't see the 'point' of continuing if I don't see anything longterm. It goes against my grain.
Same here. I need to find some new friends though or figure out a new place to meet girls, this part of the city I live in seems to be barren of early 20-somethings...