from dictionary.com,

regret:

1. to feel sorrow or remorse for (an act, fault, disappointment, etc.)

2. to think of with a sense of loss: to regret one's vanished youth.

3. a sense of loss, disappointment, dissatisfaction, etc.

4. a feeling of sorrow or remorse for a fault, act, loss, disappointment, etc.

by amy bloom,

Love at first sight is easy to understand;
It's when two people have been looking at each other for a lifetime, that it becomes a miracle.

go figure.