Why to-do schedules should be flexible

I'd drafted up a plan for the week:

Monday - menu planning
Tuesday - mend small tear in tent, pack clothing
Wednesday - grocery shopping, food prep
Thursday - pre-pack car
Friday - leave for event

But then I figured that if I did the grocery shopping today after gym, I could bike tomorrow instead of taking the car (because I don't want to end up carrying my backpack full of CSA veggies around at the supermarket and bicycles don't have trunks to leave them in). And having done the grocery shopping, I got sucked into starting the food pre-prep and the next thing I knew it was 8:30 and I hadn't even had dinner yet. So although the tent canvas is sitting the living room waiting for me, today ended up being all about the food.

I also got distracted by deciding to add another Form of Cury recipe and mix up a batch of hypocras spices. So now the leftovers of a bottle of two-buck Chuck red (which I'd cracked open for some cooking wine a few days ago) is macerating with spices and sugar for the weekend.