You’re not a better co-worker simply by virtue of slumping over your desk all night. Rather, this suggests that you have too much to do. Once this is clear, we have to face the fact that overtime does occur. The art is limiting overtime to its bare necessity, so that it at least feels relevant. And perhaps even fun. And there’s no need for you to starve or to fear acceptance of a late restaurant bill – only, don’t buy the entire restaurant.