That's a very complex topic. Taxation without representation was one thing that bothered the colonists, but that alone did not cause war. There really was very little taxation in reality. It was the "no representation" part that is broader. Being treated like children. Some areas, particularly Massachusetts, were much more outspoken about their desire to be seen as a valid part of the British nation rather than just an occupied colony. The Boston Massacre was a major turning point. A great deal of protestation occurred in Boston over that (look up the tea party, it's not how your history books explain). The British sent troops over and put Boston under a sort of lock down. Many of the other colonies responded with things like days of fasting. Unrest began at that point and numerous mis-steps by the local royal governments present caused people to seriously discuss a movement against it (ex. the gunpowder incident in Williamsburg). The Continental Congress was formed, sent a letter of grievances to the King, to which he poorly responded. Sort of a last straw, though most were still very against war.

No single thing caused the rebellion. Just many small, singular events that pushed us towards it. If it weren't for many of them, the war likely would not have happened. At least not to the extent that it did.