There are plenty of decisions I've made that were probably ill-advised, but I can't regret anything from before my daughter was born. I'm pretty confident that if literally anything had happened differently prior to her conception, then she wouldn't exist. That's just based on the vast improbabilities of DNA combination.
Focusing on the past few years, though, I would have made a different home purchase decision. We increasingly feel like we bought a Bluth and that there were better locations available.
It's not a huge deal, but it's also not an easily reversed decision.