It's more the training added to the genetic engineering. If you were trained from birth for years to obey every order given, it would take a special person to break away from that and learn to think for yourself.
The orders were contingency plans trained into their brains from birth. The chip is a really crappy way to bypass people saying that obeying every order wasn't realistic. The clones didn't obey every order exactly. That is why they were better than droids, they had to think for themselves and had a bit of a sense of self-preservation as all humans do.
As for the anger, many people with military training act calm and stable under the most stressful situations. That is with training 18+ years into a human's life. Now, imagine being trained from birth to be completely calm and level headed even when adrenaline was coursing through you. You would resort to the training and your body would go on autopilot. In a combat situation, you don't have time to think. This goes back to Order 66. It was trained into them in case the jedi ever betrayed the republic. The clones didn't get to see what was happening within the Jedi counsel and the politics of it all. The order tells them that the jedi have betrayed the republic and are trying to destroy it. After all, the clones don't work for the Jedi. Both the Jedi and the clones work for the republic. They wouldn't even have to think, they would resort to the training that they has been drilled into them from birth.
Add to that genetic enhancements that make them follow orders more. This is not impossible at all. Genes control everything from taste to size and shape to even likes and dislikes. With the technology the Star Wars universe has, there would be groups (like the kaminoens) that are dedicated to unlocking every portion of the human genome. After all, they did engineer accelerated growth to make clones ~20 in 10 years.
Karen Traviss' Republic Commando series do a very nice job of unlocking the mysteries of the clones.
tl;dr There was no damn chip. Genetic engineering and TRAINING SINCE BIRTH would easily account for their actions.