I'm glad that you recognized this early on in your career - I recognized it a little late and while I don't regret working the extra hours or burning the candle at both ends, I do think that some of the mindset and culture has hurt me when moving to a company that does not have that culture (at least explicitly). I think ultimately if you are doing what you really love doing, you won't mind putting in the extra hours but I do feel that sometimes there's other aspects of work that get in the way of the work that we love to do and we then grow resentful of work (I know I have). Barbara Corcoran, one of the Sharks on Shark Tank, has a practice where every few months, she writes down a love and a hate list - she writes down all the things that she loves doing, and then she writes down all the things that she hates doing, and then she tries to figure out how to do more of the things that she loves, and then tries to figure out how to do less / delegate / eliminate things that she hates to do. I think this is a good practice that can really help you love your job again.