Aw, c'mon, do it for ol' Gil! Essentially a parody of Jack Lemmon's desperate, beleaguered real-estate agent from Glengarry Glen Ross, poor old Gil is the ultimate sad sack: A salesman whose only asset is his expired charm. The poor guy's an inch away from losing his job, wife, house (that is, his shitty job, cheating wife, and whatever roof he currently calls home). All he needs is one more sale--just one sale, please, pretty please?--but he is completely unable to seal the deal. He practically sweats desperation.
Gil is great because he makes you feel good about yourself. No matter how miserable your life, at least you're not that guy. Like many of The Simpsons' finest characters, Gil fills a niche you didn't even know was empty till he appeared. He's like a grownup version of the Squeaky-Voiced Teen in that he pops up any and everywhere, never holding the same crappy job twice. He sells shoes, used cars, doorbells, even Coleco computers ("Now, let's talk rust-proofing. These Colecos'll rust up on ya' like that, er ... shut up, Gil. Close the deal ... close the deal!").
Gil is best when used sparingly; the perfect one-joke cameo. Pop up, make us laugh, disappear. Of course they gave him a starring episode--even Crazy Old Cat Lady is due her leading role--where he moved in with the Simpsons (and who hasn't yet stayed at that house?), but we like Gil best when he's tried to sell us something obsolete, failed, and limped away, dejected but eternally optimistic he'll nab the next one.
If you're saying "Who??," Arnie Pye in the Sky is Springfield's traffic-copter newsman with the perfect closed-nose news voice. ("Look out at the corner of 12th and Main because I'm going to be sick!") Arnie is hilarious as a second-rate reporter with an inferiority complex and a chip on his shoulder; he's jealous of Kent Brockman and so desperately wants his job. (In fact, Arnie once got to take over the anchor's desk, whereupon he instantly dropped the nasally newscaster voice and adopted the smooth tones of trustworthiness.)