In 1989, when the earthquake in this episode happened, I knew someone who looked a lot like Dan Vasser. I can't recall his name now, because he was part of a contract job - what we called Temporary Position back them. He had a sister who was in San Francisco at the time of that earthquake.
Losing someone after an argument can change you. Or not. It depends on the person, not the circumstances. Losing someone in general does change you. Period. It's not as easy to make the changes happen as suddenly... stopping.
People say quite often how cool it would be if they could travel back in time, but only if they could change something. This episode proves that no matter how hard we try, what we want is quite often irrelevant. Things are going to happen anyway. No matter what you 'want'.
Conversely, I enjoyed how the writers approach how Dan does get to change what he changes and how it affects the world in small ways, not hugely dramatic ones.
The series appealed to me the same way that Quantum Leap did. Only in this one, they replaced Sam Beckett's Swiss cheese memory - leaving out details about his real life - with the extreme difficulties a man would have if he still had that real life. They also flip-flopped our understanding of "traveling". In QL the mechanics were explained. In this one, it might have been but, well, those are the breaks when it comes to network television.