ZIP invented bt Whitcomb Judson of Chicago, first exhibited 1893.
His system didn't gain currency, and was superceded by Gideon Sundbeck's, patented 1913,tho' the idea didn't take off till 1917.

Sliced bread invented Otto Rohwedder, Missouri,1912, but idea didn't become successful until he devised a method of sealing the bread in a wrapper,1928.

Greatest idea before sliced brea - the knife.

Greatest idea since - the rediscovery of Gestalt bt Fritz Perls after WW2.