'You won't believe the week I've had.' Interesting, isn't it, how often a conversation can slip into exchanging catalogues of disasters? If you're not careful, it can end up as a kind of one-downmanship in which each competes to out-gloom the other, and it turns what might have been an opportunity to lift one another up into exactly the opposite. We part having had a good grumble, but failing to gain the lift which a truly good conversation can deliver.
Generally, though, there are ways of steering a conversation out of bluesville. For a start you can help to set its tone yourself by talking about your own good stuff (even on the shabbiest of days, there is usually some) rather than running through all your woes. It also makes sense to ask about areas of the other person's life that tend to be positive rather than the bits you know have a tendency to make them crabby. Talking about bad stuff may leave you feeling bad. But talking about good stuff... well that's another story altogether.