"But that doesn't mean to say, of course, there aren't occasions now and then - extremely desolate occasions - when you think to yourself: 'What a terrible mistake I've made with my life.' And you get to thinking about a different life, a better life you might have had. For instance, I get to thinking about a life I may have had with you, Mr. Stevens. And I supposed that's when I get angry about some trivial little thing and leave. But each time I do, I realize before long - that my rightful place is with my husband. After all, there's no turning back the clock now. One can't be forever dwelling on what might have been"
... The Remains of the Day, Kazuo Ishiguro