What could possibly go wrong?

OK, it's Saturday afternoon, the weekend before the marathon, and I decide to take a walk up to town to do a little shopping and get a decent coffee. I slip on a pair of comfy shoes that I hadn't worn for ages... it turns out that I hadn't worn them at all since I bought them on my last US trip so they could be classified as new. It's a familiar story; new shoes + long walk = hello blister! It's not too bad, just a little blister on my heel but REALLY... what was I thinking?? To be on the safe side I missed the 8 miler this weekend. I might do it on Monday or Tuesday but we're tapering off now and it's not that important.