Sets of three

When people say "bad things come in threes!" they are right, in a sense. Since bad things are happening continually all the time, then sure; you could group those into sets of three if you'd like. If dividing up the crappy stuff makes you feel like theres less of it then sure;  go for it! Can you then group the groups together after - 'bad things come in three groups of three!'

I guess that could be interpreted differently though. It COULD mean that there is three sub-groups of bad things; like categories. The Crap, the Shit and the Fuck my life. Although, the lines between these groups would be incredibly difficult (if not impossible) to define because everyone will view a bad situation in a different light!
One person getting they're arms chopped off might think its a tragedy! Yet a completely different person may think its alright - maybe the arms they lost were covered in hideously ugly moles (not that I think moles are ugly...)