Virginity by many is perceived as 'purity'; Something untainted by something as 'filthy' as sex. It's that Purity that virginity is said to be that's the entire definition
But it's hard to when you are comparing it to the ideal version you have in your head. People dedicated to their craft, say painting, will always look at their work with dissatisfaction because they're comparing it to the idealized version they have thought of.