I have a tendency to add and add features before I've even got a MVP, which often slows down production time until I get it live. I can see the "whole" of the product, but sometimes, adding those extra features takes time and thought. A current program I'm working on... I ended up scrapping at least 4 or 5 projects within the product just because I realize.. who asked for this? It sounds great in theory, but sticking to the primary purpose of the application to bring it to MVP is the real goal and the faster way to get it going.
I've probably spent hundreds of hours working on projects that never went live and I abandoned them before they ever had a chance to be taken live. So it is something I'm working on.
I suppose the only regrets I really have: I have a habit of purchasing domains for 10 years which isn't a bad price: $100 or so. However, now I own a dozens of domains I'll probably never use.