Seasonal Homicidal Disorder
A “rage incident” is usually triggered via a social networking service. The typical pattern involves someone making a status update about how incredibly cold it is where they are at the moment, followed by some smug git in a more temperate part of the world replying in a condescending fashion about how wonderful it is where they are, thus triggering an overwhelming urge on the part of the first person to hunt them down and throttle them to death with the drawstring out of their boardshorts.
Seasonal homicidal disorder by proxy
This is where the original poster is not triggered into a rage incident, but an observer in similar icy conditions. This controversial variant can be especially hard to diagnose and prevent because the lack of previous communication between the observer and the smug git means he or she often doesn’t even see it coming. Plus the general societal perception that the little prick deserved it makes this an especially hard disorder to treat.
Extrovertal homicidal disorder
This is basically the non-Internet equivalent of SHD, where some annoying little ray of sunshine living in the same bitter environs is unmercifully happy and in your face. The highest incidents of EHD occur in the early morning before a large percentage of the population has had their coffee, usually when the extrovert is trying to cheer someone up. The results can be quite gruesome.
There are many different treatments for seasonal homicidal disorder including coffee, medication, ionised-air administration, cognitive-behavioural therapy and carefully timed supplementation of the hormone melatonin.
The most effective known treatment, called STFU, is a preventative treatment where the smug little git just Shuts The Fuck Up. Unfortunately this does not usually happen until there is blood on the carpet.