Why was "tantrum" trending last week?
1836, "old-fashioned," from French rococo (19c.), apparently a humorous alteration of rocaille "shellwork, pebble-work" from Middle French roche "rock," from Vulgar Latin *rocca "stone." Specifically of furniture or architecture of the time of Louis Quatorze and Louis Quinze, from 1841. If this is correct, the reference is to the excessive use of shell designs in this lavish style. For differentiation, see baroque. The general sense of "tastelessly florid or ornate" is from 1844.
Much of the painting, engraving, porcelain-work, etc., of the time has ... a real decorative charm, though not of a very high order in art. Hence rococo is used attributively in contempt to note anything feebly pretentious and tasteless in art or literature. [Century Dictionary, 1902]
Baroque in the extreme. Used to imply that a program has become so encrusted with the software equivalent of gold leaf and curlicues that they have completely swamped the underlying design. Called after the later and more extreme forms of Baroque architecture and decoration prevalent during the mid-1700s in Europe. Alan Perlis said: "Every program eventually becomes rococo, and then rubble."
Compare critical mass.