Thursday I was struck down by a rather horrible stomachache getting off the train in the evening and pretty much had to lie down until bedtime. Andres made me some cheese toast, and I thought perhaps I would sit and be sociable afterwards while he and Cathy had their dinners, but I could smell their dinners and then I had to go lie down more.
Friday evening we went climbing. The gym played really good workout music all evening ("Eye of the Tiger" mix, lots of electric guitars; most everyone in the gym was kinda dancing a bit on their way from here to there; I determined that it's rather difficult to air guitar and tie a knot at the same time...) and I climbed all the things and was generally hyperactive and cheerful.
It's not usually quite that pronounced, but the randomly varying energy is hard to plan around.