We did it not because it was easy, but because we thought it will be easy

This is also how everything else works.

and then you turn around and realize you accidentally created a cure for cancer at some point during the process, and now you have to figure out how you did that

Reality: We have no clue what we are doing but we can calculate pi to a hundred decimal places from memory.

Sometimes it's not like this though.

Sometimes it's the solution that's complicated

Good rule of thumb: if someone else hasn't solved the problem yet, it's more complicated than you're assuming. If the problem is worth solving, other people smarter than you have almost certainly attempted the easy "solutions" already, and they were inadequate to solve the problem. Heck, even if it's not worth solving, there's a non-zero chance that some pre-Reagan weirdos took a crack at it with bonus mercury and thallium compounds for the lulz and published it all in a vague 200-word comm in a now-defunct journal.

o shit, is that economics or sociology in the science memes subreddit?