But sometimes, grappling is used for wonderful, amazing, hilarious things. That said, very rarely do grappling rules seem at all intuitive or useable. Usually the players and/or GM will groan when a grapple begins, as they try to dig out the rules for it.
GURPS grapple rules seem a bit more versatile and friendly than those of many systems, such as D&D. D&D treats grappling as automatically dishing out minor amounts of damage throughout the duration, with a few other options like trying to move the grappled thing around. Shadowrun barely even mentions it, calls it "Subduing" and pretty much treats it as "successful hit=opponent is immobilized until the break out", with the options of doing minor amounts of stun damage, trying to get a better grip, or trying to knock down the opponent. Simple, but leaves a lot to be desired by players wanting to do ridiculous things.
GURPS, particularly once you look at techniques such as those found in Martial Arts, allows for all manner of things to be done. Occasionally there are rules that don't seem quite accurate (sacrifice throw is only available through Judo, despite the Suplex being the most well-known example of a sacrifice throw, used in wrestling. Well, "wrestling", at least.