The point about miserable songs is that they can make you feel better. Of course if you're really miserable I can imagine they could tip you over the edge. But I think happy songs would be much more likely to do that.

And of course there is plenty of happy country music.

Perhaps what happens is that, feeling really low, you tune into listen to a miserable song to help you make it through the night. And out comes some really jolly number about how happy everyone else is - and it leaves you feeling that you can see no alternatve but to blow your brains out.