stumbling on happiness
We are incredibly bad at imagining how we will feel in future scenarios
For example, it's easy to imagine that I would be pretty happy if I were Mark Zuckerbug. I would have more money, power, and status than I would know what to do with.
When imagine ourselves in a future scenario that we think will make us happy, we tend to fill in and leave out details that we assume will work themselves out.
When I wrote that sentence above, I immediately assumed that I would have a completely happy marriage, happy family, despite the fact that his work life balance is probably borderline non-existent because you can't have all of that and have free time, let alone hobbies.