Ask HN: Pivotal Decisions

Discussing my 'big decisions' with my wife and why I'd made them, I commented that we frequently don't realize the impact that decisions will have on our lives at the time we make them. The impact doesn't play out in some cases for decades. That made me think that perhaps we'd all benefit from some real-life examples that might help us to be more tuned-in when those moments arise: What are some examples of pivotal decisions you made at least 10 years ago, for better or worse, and what was your thinking when you made them?