Every. Damn. Time.
I swear, cats just save up vomit and claw-sharpening for the moment you close the door and leave for a few days. That click of the door latch unleashes hell, in furball form, to ravage everything you own. We had just returned from a week-long snowboarding trip to find the couch all slashed up and little pools of sticky barf strategically placed around the apartment. The cat, of course, was purring as though nothing at all had happened while we were away.