In an interview he explains that when he went to a record store, he didn't get recognized at all. When he went to the dump, "Twelve guys surrounded my car."
In another interview, when asked what his first instrument was, he replied, "I don't know... probably a box, or something."
For that matter, go to YouTube, search for "Tom Waits interview". Any one out of the whole bunch will contain a crowning moment of funny. The fireplace-shovel with the image of the devil on it, for instance. "It's like some kinda primitive e-mail."
"Step Right Up" , "The Piano Has Been Drinking" and "Pasties and a G-String" from Small Change.
"The Piano Has Been Drinking" has the line "the owner is a mental midget". The off-key piano playing just seals the deal on the song.
It borders on Cloud Cuckoo Lander behavior, but — another CMOF came during the episode he guest-starred on John Lurie's fishing show. The two spend a couple days in Jamaica fishing for snapper, and the first time Tom catches one, he gives in to the impulse to put it down his pants. And leave it there for a while.
It may be meant as a scathing satire, but I'd still say "Frank's Wild Years" from Swordfishtrombones is pretty damn funny.
The spoken word piece "Missing My Son" from "Orphans: Brawlers, Bawlers & Bastards". - though it's just his own variation on a well-traveled urban legend that he's stretched into a Shaggy Dog Story, there's just something about his delivery, as well as the fact that the deliberately underwhelming punchline is followed by a brief pause and a deranged-sounding wheeze of a laugh.
Watching a video that "lip"synchs his song to footage of Cookie Monster.