When saying "we", do you mean you write code for the space missions?

Writing only happy path code as a standard practice in the space sector seems quite absurd. You won't ever achieve absolute precision and errors do happen, yet it seems like systems recover most of the time.

Recently, the antenna of Voyager 2 got misaligned, but it is expected to recover from that. That was only the last problem it encountered over its very long mission - and it managed to recover from all of those so far!