Let’s go back to my earlier dating metaphor (see posting Feb '09)… Marriage doesn’t have to be the next development from a dating situation. Mentoring or a job offer is not necessarily the next step after a coffee.
Friendship. Work association. Finding an idea for a project - all viable alternatives.
We don’t need to know the outcome in advance. Continually meeting up with folks (new or known) offers a chance to try something and find it (not) to your taste. If you don’t leave room for experimenting, you can’t be sure your end result is as fulsome as it could be. You also don’t have a breadth of experience from which to gauge situations, advice or opportunities.