Bali is very different from the rest of Indonesia. One thing is the religion. When the Majapahit Empire fell, lots of little empires sprouted, fighting against each other. The majority of these small kingdoms adopted Islam, almost 90%, though Bali took Hinduism. So nowadays, they have their own form of Hinduism, which I think changes the feel of the Bali a lot.
Another difference is the tourism. I think it has a lot todo with the Hinduism which pulls in people from America and Europe. But of course, Bali is also just beautiful, relaxing, and nice. If you read Julien’s blog about “Bali’s problem,” you can see how tourism is kind of bad. Though it is also good since it gets a lot of jobs for locals and the visas etc. help the goverment.
Also, the population compared to Indonesia is small. The population of Bali is 4M and just the city of Jakarta is 9M, more than double. Indonesia’s total population is 260M not including Bali, so that is a lot of people in Bali, but not that dense in population.
To round up, I have not been to the rest of Indonesia, so this might not all be that accurate. Although there are similarities, like the food and others, but everything still just feels a little different.