It's safe to say that Gaudi is one of, if not 'the', most famous architect in Barcelona. His unconventional style is world renowned, and his buildings are absolutely amazing. There's no way you can truly experience the essence of Barcelona (no matter how much paella or how many tapas you eat) without visiting at least one or two of Gaudi's famous pieces of art.
That evening we ended the tour by visiting what may be his most famous work of art... which is still a work in progress. La Sagrada Familia is a structure which is hard to describe in words, and pictures don't give it justice. On the one hand you're left feeling that the building is way too cluttered and too much for your senses to absorb. On the other hand, though, you stand in awe as you try to see every inch of detail on the cathedral facade. Every nook and cranny on the building houses a statue depicting of the life of Christ. Hours could pass and you would still feel like you haven't seen everything Gaudi was trying to represent, along with what the current builders are trying to complete for him. It truly is a magnificent building.
So, in response to the question given by Goudi's city contractor of whether he was insane or an absolute genius, I'll take a venture and say he was probably a little bit of both.