John's temperament lately, it finally occured to me, is a result of all the medications he's taking. Phew! Nasty as he's been- yes, John, nasty- I was beginning to think I was married to a man who was becoming a caricature of a crotchety retiree.
Nah- it's the Keppra, Metaprolol, Zocor, Dexamethasone, Ranitidine, Altace, and Hydrocodone (see http://www.nlm.nih.gov/medlineplus/druginformation.html).
Glad I finally figured it out!