extreme example: you could walk by your dual who could be an istp homeless crack pot... Who knows why he got there... just keep walking by... Spare some change? No sir.
we walk by our dual everyday, when I catch an enfp and they are attracted they will throw a smile. That shit makes my day. My eyes just expanded and went VERY and I was almost frozen by just her smile. Will I ever see her again? Probably not.
You could be staring at your dual on the bus on the way to wherever and they could give you all these smiles or pretend you arent there. They might be high or drunk...
They could be an abusive relationship... They could be with their dual already. There is an infinite amount of factors for 'making it work'. I can relate the ISTp frustration, ENFps can seem ADD with people and get bored of you quickly... This is often because the ISTp didnt show enough signs though. The ENFp will give you windows of opportunity when they are single and knowing when to pounce on it is half the fight for us ISTps. Its hard to give signs because around your dual you are completely yourself, and ISTps when we are completely ourselves are cold mofos who wont really demonstrate too much emotion. Perhaps going for a glass of wine after a movie would help calm the nerves... The problem for the ISTp to initiate the physical contact (as can often be the responsibility of the sensor in the relationship) is that he or she doesnt have 100 percent certainty. The ISTp is a creature of pride. With experience the ISTp learns to overcome this, less they become bitter and isolate themselves.
Oh well as long as you have a pension!