I think embarrassment really comes from writing code that you thought was great and then you look back at it and read it and it's too confident for it's own good. Learning is a gradual process–I'm almost never embarrassed by the code I wrote in the past, but that's not because that code is perfect; it's just that I made the best choices I could at the time, and made sure to know enough to identify what I didn't know back then. Embarrassment stems out of not knowing what you don't know and acting on that.