It could be any number of things, I suppose. This is quite obviously the end of another week at work. There won't be many more of them, either. Just one. That's not many. It could be the loss of the few hundred quid I'm due to pay out to the plasterer, but I think that that's not so much a loss as a gain - of some plastering.
It might be that Les Misérables, which I've not listened to in a bit, is stirring up a sense of emotion that I find uncomfortable to be experiencing during working hours.
It might be that my brain is not firing on all cylinders at the moment. Do brains even have cylinders?
It might be that a thread on another blog, which prompted me to dig out a song I wrote a few years ago, expressing the loss of a relationship, has awoken some sort of feeling or some sort. Feelings? Me?
It might be that I have a lot of things to do, almost all of which need to happen outside of this building, and none of which I feel on top of.
Or maybe my car has been stolen from the office car park while I've been sitting here listening to musicals. I'll find out when I go to where I left it in a few hours.