Green’s Dictionary of Slang

1. an excl. of surprise or shock.

1968		L. Wolf Voices from the Love Generation 169: ‘I hustled my cock on Broad Street.’ ‘Isn’t that too much!’.
1979		S.F. Examiner and Chronicle 1 Apr. A:12: It’s just toooo much (late ’40s). A real drag (’50s), a bad trip (’60s), and, naturally, a gross-out (’70s).

2. an excl. of pleasure, satisfaction, excitement.

1944		‘Jiver’s Bible’ in D. Burley Orig. Hbk of Harlem Jive.
1953		‘William Lee’ Junkie (1966) 150: They jump around and say, ‘Too much! Crazy! Man, let’s pick up! Let’s get loaded!’.
1969		Gandalf’s Garden 6 n.d. 11: too much: an expression of delight, amazement or incredulity; great, nice, splendid. (From drug experiences where the sensation is overwhelming and almost too beautiful to take).
1975		J. Wambaugh Choirboys (1976) 165: ‘Too much!’ Francis exclaimed.
1989		M. Dibdin Tryst 152: Wow, man, out of sight, too much, heavy.
2012		W.D. Myers All the Right Stuff 193: ‘We’ll give you a ticket for interfering with our job,’ the street cleaner said. Too much.