Documentation. Supposedly the bane of every programmer, system administrator, or techie person who'd rather be Doing It than Writing About It. Those same people are also the first to complain about any lack lustre documentation of technology they're trying to use, once again proving that irony is not dead. Therefore, I'm going to complain some more, because it might make me feel better, and because I think I've got something else to say along the way.
For a holiday project I'm enhancing Cookiemaster to be able to force cookies for your choice of domains to be Session (transient, go away when you close the browser) rather than persistent. In doing so, I found it wasn't parsing the date in 'Expires' correctly, and in discovering why, I found the horror that is the Date format as specified in the RFC.
Through my online lifetime, I've have a variety of preferences in terms of web browsers. For a long time it was based on personal preferences; now it's based on hard technical facts.