There are two elements to get a good, quality relationship started.  It's all about timing and chemistry.  When both are in place, it seems relationships go a little bit more flawlessly than you might have anticipated.  It's true when you know you know, and the timing will be right.
When is it the right time?
Sometimes we meet people in our lives for a reason.  You might have the best chemistry with a particular guy, but in the end, he doesn't make a move because something might not be right.  Brenda and I discuss Steve Harvey's book Act Like a Lady, Think Like a Man.  In there he describes the 3 P's man needs to have before embarking on a relationship which is provide, protect, and profess.  Instinctively, if a man, for whatever reason, does not feel he's at the capacity to provide for his family, he might distance himself from the relationship.  Not to discredit any gender roles but this is something that is engrained in him from how he was raised and his primal instinct to be the head of the household.
Another scenario is when one of the parties has just gotten out of a relationship.  They might not feel emotionally ready to get into a new one.  As the saying goes, if you love something, let it go and if comes back, it's yours.
Good on paper
During one episode of our beloved Sex and the City's Twenty-Something Girls vs. Thirty-Something Women, Carrie meets a doctor who is good on paper but there is no chemistry.  Regardless of how much she pushes to make it work, the butterflies in her stomach do not appear.  Loving relationships need chemistry.  Something to make your heart do backflips when you see the person open the door or puts a smile on your face when they simply touch your hand.  It's that thing we can't explain.  Without that, then we're just settling for what is good on paper.
Timing and chemistry are two of the most important things to fulfill prior to starting a relationship.  
On another note, if your life were a romantic comedy, which one is it?  Let us know in the comments.  We would love to hear from you.