Same here! And i'm not sure was is masochistic about it; I still write software for the MSX2 like that now ;) I only knew about Hisoft assembler and that was too expensive so I never learned anything different than opcodes.
http://pastraiser.com/cpu/i8080/i8080_opcodes.html
allowed, after some short time without even looking at the table, to type the binary code directly in (our preferred way of the Forth words implementation back then, on Russian 8080 clone of course :).