unit tests don't just save me from extra work on regressions introduced by someone else's changes somewhere, they also help the other developers find bugs in their code. now when unit tests fail on my code, i am thankful that someone wrote that test or else the bug might have slipped into the code unnoticed.
not to undermine the role reviewers have in making sure that the code isn't sloppy or missing some edge case somewhere. i learn from reviewers (senior devs) the way to think about edge cases and potential bugs, how to find them and squash them.