I admit I am a creature of routines. I write at certain times of the day. I know dinner has to be started at a certain time, school drop-offs and pick-ups are at certain times, etc. I've been like this since my children were tiny; when, I think, any sense of control made me feel just a bit saner.
But, irritatingly, the unexpected always happens. For the last few days, the unexpected has been our house internet has decided to become, shall we say, eccentric. Sometimes it works, sometimes it doesn't. It is being looked at (tomorrow) but until then, if I have to get on the net, I've got to leave the house. In fact, I'm writing this at a local coffee shop.
The unexpected happens when we're writing too - although, to my mind, this is usually a good thing. We get a character saying something we didn't expect which suddenly opens up new avenues of plot or sub-plots. Recently I had a character I'd always thought was shallow reveal his deep feelings of low self-esteem. This explained his actions and priorities on many different levels and saved him (for the moment) from the chopping block.
Detours in a plot are simply unexpected twists. For a mystery writer, this is a good thing. When I'm writing a first draft, I simply go with the flow and let the writing go where it will. It's during the first rereads that I discover (sometimes) that the twists actually go nowhere and serve no purpose or the twists aren't twists at all, but circles. There's also the delightful realizations that plot points I thought were unspeakably clever, are actually unspeakably stupid. But I digress...
The bottom line is, detours in writing can be good. Detours in life can be annoying. Or, just perhaps, they give you a chance to glimpse something new that you would never have seen while wearing your usual blinkers.