Found this and it's pretty interesting - 'Deep Regret' disease for guys

By definition, Deep Regret is the acute anxiety or inevitable apprehension trigged in the average male by the sudden or unexpected appearance of an immensely beautiful girl he innately knows is way out of his league. This girl is so gorgeous, so exquisite, so stunning, he becomes instantly enamored beyond mental functionality and can barely keep his eyes from popping out of his head, let alone bring himself to speak to her. Her beauty and elegance, her feminine mystique are so intoxicating, so staggering, his knees involuntarily go weak, he becomes unreasonably inarticulate, and as a result, just stands there like a n00b with his jaw on the sidewalk. Naturally, she takes zero notice of him and doesn’t even acknowledge his existence as she gracefully strolls away out of sight, and ultimately out of this life forever. It’s not a conscious thing on her part; she’s not being discourteous or mean by any stretch of the imagination, she’s just that sweet, innocent and utterly charming. She simply has no idea.

Okay. Never for a second have I pretended to have the ever-elusive female charm all figured out, but I can certainly speak for the impending inhibitions that we shy males must deal with. I’d tried to give this crazy phenomena a suitable title for a long time until Pete finally hit the nail on the head. Deep Regret refers to the irresistible longing a boy has to approach and speak to his dream girl even though he cannot physically or emotionally make himself do it. He is trapped in inner turmoil. Stricken by quiet chaos. Utterly helpless. Paralyzed. Despite the inner machine gun spray of stinging desperation, he watches her walk away and spends that night staring at the ceiling wondering WHAT WOULD HAVE HAPPENED had he found the strength to fight back the nerves long enough to say hello. His chance is lost, she is gone, yet he still replays the scene in his head, wishing he wasn’t such a jellyfish around pretty girls. Who knows what might’ve happened? He kicks himself. The wondering alone could choke a moose.

That, dear friends, is Deep Regret.