I think he's on steroids again, and that's why he's so cranky.
Has Don Draper met his match in his cranky, incompetent new secretary?
If India's economic miracle turns out to have been a mirage, it will not be so easy to dismiss that kind of talk as cranky.
"cross-tempered, irritable," 1807, from crank (n.) + -y (2). The evolution would be from earlier senses of crank, e.g. "a twist or fanciful turn of speech" (1590s); "inaccessible hole or crevice" (1560s). Grose's 1787 "Provincial Glossary" has "Cranky. Ailing sickly from the dutch crank, sick." and identifies it as a Northern word. Related: Crankily; crankiness.
Ben. Dang it, don't you spare him--A cross grain'd cranky toad as ever crawl'd. (etc.) [Richard Cumberland, "Lovers Resolutions," Act I, 1813]
Very irritable; touchy: The baby was cranky all day (1821+)