It's not something that plagues my thoughts, or causes me regular distress. It's just something I look back at with regret. No matter what you have, I think it's kinda hard not to feel some sorta way about a decision that cost you $400k. Especially if you didn't grow up with money.
I've never been cavalier with money, and no matter what I have, I don't think I'll ever be one of those people who wastes money for the sake of wasting it. I'll never be someone who lights $100 bills on fire as a way of showing off. Even if I could afford it. The way I grew up, and what I was taught about money in my youth is still with me. And I think that's a good thing.