I hate the US patent (and to a slightly lesser extent, copyright) system. It is stupid, inefficient and unjust. It doesn't make any sense in the modern context of software and algorithms, results in millions of dollars of expenses just for the lawyers (not including infringement judgments), and none of this money goes to anything productive whatsoever. As with the recent lawsuits against app developers, the infamous SCO linux lawsuit, etc, these patent trolls that have never done anything productive can sue major companies that do real things for billions of dollars. Or alternatively, sue tiny app developers that can't afford to protect themselves (this is like a twisted version of the RIAA/MPAA copyright infringement suits, where the P2P infringers could not afford to protect themselves either and would accept settlements to limit their liability).
Furthermore, I hate the system because the people promoting the system are the large, pre-existing giants who use patent portfolios to protect their fortunes, so they have no incentive to change it. The small and new players don't have the resources to fight the system and fight for change, and common ordinary (i.e. non-technical) people don't understand how it works so they don't understand how broken it is and how much damage it inflicts, so they don't try to change it either. That is a byproduct of how complex and arcane patent law can be (not to mention, the things being patented are themselves also typically complex and arcane).
P.S. No offense to the US PTO or trial judges. This is a complaint about the rules, not the people who enforce them.