According to Eric Berne's 1964 book Games People Play, Schlemiel is a head game for 2 played in social situations.

The Schlemiel does indeed spill soup on the Schlemazl, and apologizes.
The Schlemazl responds by forgiving the Schlemiel, thus allowing the Schemiel to continue with their pattern of minor offenses.

The payoff is the Schlemiel gets to be an oaf, and the Schlemazl gets to be the long-suffering martyr. Both parties benefit, and the game can go on for a lifetime. If the Schlemazl does not play "properly", and takes offense, refuses to forgive, and kicks the Schlemiel out on hir ear, the Schlemiel gets to resent them for being mean.

The way out of this game is for the Schlemazl to forgive the Schlemiel in advance for anything they might do on the condition that the Schlemiel may not apologize for the offending behavior, and then stand back. Preferably behind a solid object.

Sorry about the screwed-up link in the previous version of this w/u. Guess I'm the Schlemiel...
Oops, there's another one. Schlemiel apologizes again.