I'm so tired of "experts" wanting you to barter with children when their behavior is unacceptable! Buying the candy bar, even if it is for later, is saying to that child that throwing a fit got you exactly what you wanted...the candy bar....he doesn't care if it's later or not, he got it! Next time he wants something, guess what???...a fit gets results!!
Why don't parents today want to set boundaries...you may not have the candy bar, period! The child then sees that throwing a fit will not work...and if you are consistant with setting limits, then he will begin to realize that bad behavior does not get any rewards!
Giving a child 2 minutes to throw his fit is again telling your child that that is acceptable behavior for 2 minutes. If it wrong, why let it continue for any length of time?
Take the child away from the situation and do not make "empty" threats..."If you throw a fit, we will leave the store and you will have time out when we get home!" and follow through!! Go back to the store after the child is bed or later without him, while someone watches him....do not let him go back with you that day, he lost that privlege!! I'm tired of parents not wanting to be inconvenienced or wants to be the child's "friend". You're job as a parent is to set boundaries! Try it! It works! Be consistant! If he gets his way some days and not other days, he gets frustrated and you'll have more fits!

We have narrowed down my 5 year-old's tantrums like this:
they NEVER occur in school or camp
they ALWAYS occur at home, in public places and, especially when he wakes up in the morning.
Sadly, i will have to deduct that they are occuring while either one parent or both parents are with him. We can try to 'ignore the screaming, kicking and crying' or send him to his room for quiet time, or physically remove him from the situation - but nothing seems to help.

They are very long, loud, sometimes violent tantrums.

any suggestions?