tantrums -- this too shall pass???

"Usually by the time a child is three or so, tantrums are a thing of the past" -- popular parenting advice giver. Hahahahahaha. From my experience at least, the threes are more terrible than the twos. They are so much smarter and more capable and they know just how to press your buttons and they have perfect timing on when to pitch a fit. We have been tantrum city here lately. Isaac is such a strong will child and I am getting exhausted going toe to toe with him day after day. It could be anything that sends him into a grand mal tantrum. I say no to icecream for breakfast. I accidently flush the toilet when he wanted to. I serve him chicken (a normally highly preferred food) for dinner. Next thing you know he is down on the floor, kicking, thrashing, screaming until he is hoarse. Parenting books say to ignore him but he often grabs onto my legs or follows me around from room to room throwing himself at me, yet refusing any attempts to hold, soothe or comfort him. Target is a frequent location of his worst tantrums. I fully admit that I have reinforced tantrum behavior there by purchasing him toys and candy as a way to avoid public meltdowns. He recieves inconsisent messages from me (and other caregivers) and he definitely uses his tantrum behaviors as a weapon-- a means to an end. I have more than once left a cart full of groceries behind and hauled him off to the car. One time it erupted in the checkout line. I really needed whatever it was we were buying and I wanted to pay and get out. There was an old lady in front of me who was taking her sweet time paying and kept trying to talk to Isaac and me about the tantrum the whole time. "Well what is it he wants? Surely you could give since he is so sad". I attempted to ignore the woman and she finally left so I could pay and haul my screaming son out to the car. I manage to pay for my items, and I attempt to keep one hand on Isaac who is beet red and screaming bloody murder while juggling several heavy bags. We leave Target and he realizes he really isn't getting the toy and he kicks it up another notch. We are both sweaty and I am near tears myself. Well wouldn't you know our friend from the checkout line is parked right next to us and is continuing to stare at me, mouth agape. My plan was to trap Isaac in the car and then attempt to calm and quiet him, or if nothing else to strap him in and drive the 2 minutes home and then deal with him. Of course, he is still set on his toy and is fighting me tooth and nail to get into the carseat. Our elderly friend decides to intervene again. She approaches me. "Excuse me, what is it he wants? Little boy, what is it that has you so upset?" I ignore her and continue to try to stuff Isaac in the car. Please note, I have not spanked Isaac, yelled at him, or done anything in appropriate. I am simply trying to deal with him. "Please, what is it he wants? There must be something you could--" I spin around to look at her and Isaac uses this moment to make a break for it across the parking lot. I take off after him all the while I am screaming over my shoulder at this woman "PLEASE JUST MIND YOUR OWN BUSINESS!!!!!" Fortuneatly Isaac was intercepted by a woman who told me I was doing a good job and offered to put my bags in the car for me. So anyways, now if I ever see a mom dealing with a kid in public, I try to give her a sympathetic smile and I say a little prayer for her.