This was initiated by a conversation I had recently with a guy I dated a few years ago, who apologized for our relationship ending, saying he realized later on that he had made a mistake and regretted our separation.
It humored me that he was one of several guys who had said this to me, and it got me thinking that this could be an INFJ thing. Our personalities don't shine or glitter or attract attention from another side of a room. We don't advertise our depth or our capabilities.
In my case, the guys that have had an opportunity with me, and the attraction was mutual, it was because they had gotten to know me and found something worth getting closer to... perhaps because I made them feel comfortable, liked, understood, etc. But, in nearly every one of these cases, they were distracted by another girl, who was shiny and glittery and demanded their attention and ultimately, only kept their attention to occupy herself and for her vanity. Other cases could be blamed on the guy being young. I'm sure they sensed a necessity of commitment when it came to a relationship with me. I am not the flighty type. I don't easily allow my heart to wrap itself around something I don't intend to keep around for more than a few months. Anyhow, this probably caused them to seek elsewhere, and then later have a change of heart in what they desire and realize all along that I could've provided that.
Yes, that sort of thing likely happens to everyone at some point. My argument is that this probably happens to INFJs much more frequently, due to our personalities.
(I was working on writing more, but got pretty distracted and lost my train of thought).