A colleague of mine likes to quote: "You can't succeed by the quality of your excuses", and it is unfortunate that this quotation comes in handy as often as it does.
I'm quite willing and able to be sincerely sympathetic to a student or colleague with a complicated life that involves numerous consecutive problems with relationships, family, health, vehicles, computers, housing, and pets, but all of these excellent reasons for not making adequate progress in research add up to career destruction.
There are some life events that are clearly too terrible to allow life/work to continue normally, and I am not talking about that kind of event here. I think that it is, however, important to be able to work through the routine awful things that happen in life. For example, if I didn't submit my NSF proposal because I was too broken up about the recent death of my beloved 17 year old cat, my research program (including my students, postdocs, and colleagues) would be harmed. Aside from the fact that I would rather keep working than brood, it's just not an option to shut down.
Yet I work with some people who routinely do things like that. Perhaps I am less 'sensitive' and more of the stereotypical unfeeling scientist than they are, or perhaps they are less able to deal with life. I know which of those possibilities I prefer, but I think there is probably an element of truth in both.
I like to think, though, that working through bad/sad times is similar to how you have to keep yourself together and take care of your child even if you are stressed, sad, or anxious. I don't think this is something that I, as an advisor, can teach my students, even by example. Or, if it is possible, I have not yet figured out how to do it well.
8 months ago