I have plenty of financial regrets. The emotional ones. . . eh, I figure they led me to where I am now. And, had I not had a few failed relationships, I don't think I would have learned the tools necessary to have a great marriage with my husband. I learned a lot from those earlier "mistakes", and I'm pretty confident they prepared me well (although painfully) for marriage with kids. Which, I find to be not for the faint of heart.
Also, your cabin regrets make reinforce how happy I am that we are planning to keep our vacation house. It's near family, so close enough that it gets a lot of use, but also a great place with tons of memories.
Financial regrets:
-Should have sold our Seattle house before we missed the 2 of 5 year window for taxes. This was preventable, but we completely shifted our thinking on where we would settle down until the kids were out of school, so . . . in the end we sucked it up & made do. But, it was an incredibly expensive change in plans. Six figures.
-Wish I would have not treated shopping as a hobby in my 20s & 30s. Just a waste of time & money, neither of which I can ever get back.
Other than that, I've made plenty of smaller mistakes along the way & could have been just generally more frugal, but the two above would have had the biggest long term impact.
I'm about to embark on a pretty significant life change in 2018 (giving up my high paying job & spending more time with the kids). I know if I don't do this, I'll have major regrets. So, hoping to prevent that future regret.