LTIH: While accelerating hard off the lights up a short hill on my way into the city, I suddenly stepped on nothing and went arse over apex. Turns out that my Shimano Ultegra cassette has let a single cog go, rotating independent of the rest of the cassette. This has happened to me once before, and I have never heard of it happening to someone else. I am really pissed off, it's as bad as a chain breaking but far less understandable because of how well reinforced that area is. How have Shimano's standards fallen so low? They used to make absoutely bombproof gear.