Is consciousness just an illusion?

Well, the straw in the water example isn't an example where you're seeing things incorrectly first off. It's an objective fact, not dependent on perception, that from particular reference points, reflections of light waves from a transparent glass/liquid/straw system are such that the straw looks bent within the liquid compared to outside of the liquid.  


The misconception there is a theoretical misconception, it's not a perceptual problem. And that theoretical misconception is one where reference point property variance facts are taken out of the picture, and we conceptually interpret data to be telling us or not telling us "what the straw is really like from a reference point-free perspective."

There are no reference point-free perspectives, though, and from particular perspectives, what the straw is really like in terms of light waves at that perspective is that it is bent below the water.