Tantrums, Tantrums, Tantrums!! What is with toddler tantrums???

Son throws tantrums. Massive, loud, obnoxous tantrums that often manage to get me out of my skin. He throws them at home, in a restaurant, in the store, while he is (supposed to be) eating, in the street when we disagree on the subject of sitting in the stroller, on the bus (just because he can). He screams endlessly while I am trying to balance 63 things in my hands while making sure he doesn't fall off the cart and pee in his pants (Son tends to pee while crying) in Costco, he screams in Target if I refuse to buy him 35 different cars, he screams while we are in line at the supermarket simply because he is bored, he throws himself on the floor and rolls around howling if I don't let him watch Elmo. One place he does NOT scream anymore is the car. Go figure.
Let's see what the magi say:
The Almightly Sr. Sears (whom I dislike) on tantrums: "You send a clear message when you ignore his fits or walk away. This teaches him that tantrums are not acceptable. This is part of toddler discipline." Um, Son can go on for 20 mins or more. Ignoring him does nothing...what else you got?
Babycenter on tantrums: "Staying with your child during a tantrum is a good idea. Stomping out of the room — alluring as that may be — can make him feel abandoned." Well, but here's the thing--if I stay with Son during the entire tantrum, there is a distinctive possibility that I might toss him out of the window at some point. I am fairly certain that it is better for both parties involved to remove myself from the scene at home.
This is what I do outside of home: I freeze my face in a pleasant, possibly slightly psychopathic looking smile and give looks with it to everyone who is staring at us. I also pretend to know exaclty what I am doing while saying things to Son calmly in a foreign language while he flails and screams. In my head, I hurl obscenities at the 20-month old and invent various alcohol recipes that I am about to try the moment we enter home.
The MayoClinic has this pearl of wisdom: "If you sense a tantrum brewing, distract your child. Try making a silly face or changing location. It may help to touch or hold your child." My son is 20 months old--making a silly face worked when he was 3 months. And it's tough to change location when you are finally approaching the cashier on an endless line.
So, where does this leave me? Nowhere! But since this is mommy's world and her rules, Son will just have to suck it up and do what I say. This morning, he refused to eat breakfast even after I broke down and put some Elmo on (oh, judge me galore, I don't care, YES, we do watch TV during meals sometimes. I certainly prefer that to malnourishment). Then I threw a tantrum of my own, stopped the TV and told him (calmly, I assure you!) no more Elmo till you eat your awesome breakfast. Voila--tantrum! I gave him a time out in his room. After yelling for about 10-15 mins, he finally calmed down. I still have not been able to. When is too early to whip up a martini?