The funnest thing about these is how quietly and slowly they creep on. It may start with putting off a few things but then one day you realize you haven't showered because you feel like you don't have enough time for it.
Sidenote: that's why behavioral studies never ask "How often do you run" but instead "When was the last time you ran?", or even better "Describe the last time you X". People are terrible at assessing their general performance, but great at recalling semi-specific events.