Hi E. -
Welcome to the three-year-old club! :) Everyone says that twos are terrible, however, with my son, he was definitely at his worst when he was three. He's four now, but sometimes gets into his ornery, stubborn moods, especially when he knows he has an audience (i.e. at the grocery store, the mall, and/or his Mammaw's house, etc.).
His most recent episode was at the Post Office, where we were standing in a rather long, slow-moving line. As soon as people started paying attention to him, (which I knew would happen because what else is there to do while standing in line?), he started acting CRAZY - jumping around, scream-singing, basically the works. My two-year-old, who's her brother's shadow, thought it was hilarious and joined right in. Soon they were both running around the whole lobby and nearly knocking people off their feet. After about one minute of unsuccessfully asking them with an even-tone to come back to me, I dropped my tone very low and got really stern, but that STILL didn't work, so I asked to have my place saved in line and went to plan "C," which ALWAYS works whenever I employ it...I pulled their hair quickly and firmly by their temples and they immediately stopped their mischief.
Knowing I had a rapt audience by that time, I was all too prepared to hear whispers of disapproval, but instead I got some positive head shakes and the man who was standing behind me - a pediatrician I later found out - actually said that was the best way I could've managed that particular situation. He said spanking may have worked too, but who really wants to see kids get spanked in public? - it's embarrassing for the kids as well as for those around who are forced to watch. The doctor went onto say that a quick tug on the hair by their temples or at the napes of their necks not only stops bad behavior immediately in young children, but makes them more open to listening to what you have to say because they are effectively restrained and in control of their own pain levels. Hair pulls are usually my plan "B" at home (Plan "A" being always a fair warning), and up until that day, I was always reluctant to use this technique in public because of my fear of judgment, but I won't be wary any longer. This method is quick, discreet, effective, and most importantly, it doesn't inflict any long-term physical damage. If a pediatrician can see the merits of this method, then I can too.
Bottom line, some toddlers respond to reason, but most don't and need more stern discipline. My kids are mostly reasonable, but when they're not, I'm not going to waste time running through a gammit of textbook methods when I need them to stop their behavior immediately to prevent possible harm to themselves or to others (i.e. running out in parking lots, knocking people over in crowded areas, hitting others, etc.).
Blessings to you and yours.