The ones I think about the most were the ones I never got to do the biz with. Perhaps they'd have worked out better than the ones I did get homely with, or perhaps not.
I once knew a woman at work that I got on very well with, and most importantly we had a lots of laughs together. She was married at the time, and when her husband died in an accident she had remarried by the time I found out.
I met a few in my life that I really liked, and might have made a go of it with, but as usual, the ones I liked didn't like me that way, or someone else got there first. The most beautiful woman I ever had a friendship with unfortunately had a flat mate that disliked me, so that one never came to anything either.