One gripe I'll hear sometimes when showing friends new music is, "It's boring because it's too repetitive." On the other extreme end of things is this—a piano sonata that has no patterns or repetition of any sort whatsoever.
Titled "The Perfect Ping," the piece was composed using a Costas array, which is a mathematical grid of points that is typically used in sonar. Even the rhythm is completely unique, with each pair of notes having a different starting time within the measure (which is apparently almost mathematically impossible). The end result... well, see and hear for yourself.