I am a firm believer that if your child really misbehaves, you have to look no further than your own parenting.
Parents can really dig themselves into a rut by basically being crap parents from day one and letting their child run riot. Children learn from a very early age what they can and cannot get away with and they will take what they can get.
I am very calm with my child and so is my partner. He is as good as gold 99% of the time, unless he is tired or hungry or bored.
I always keep some easy to eat fruit for him, like grapes, blackberries or olives and it works all the time. If he is bored I just get out one of his books which he can learn from. I use one book at the moment with pictures of lots of different types of vehicles and I teach him what they are called. I only started on this book about a month ago and he already knows 26 different types of vehicle and he is only 18 months old.
Better that than a child being brought up in a home environment destined for life of crime etc
If I know he is likely going to be tired, I just will not take him into a situation where I cannot put him down if he does.