Think of all the the time each day you spend in Bed. Naturally, you can't take home where you usually sleep during the day, your work desk. Therefore, Bed is the most important place for sleep at home, limited by modern pressures to just 12-14 hours a night. And everyone needs sleep. How else would you make snoring noises and shout out embarrassing things in the middle of the night?
Almost as important is the other thing associated with Bed. That is is your other good friend, Pillow. Unlike Bed, you can fold, fluff, punch and fling around Pillow. Pillow is made of special materials designed to absorb your slobber and prevent you from drowning. Plus, it allows you to have pillow fights, where Bed fights tend to get out of hand rather quickly.
Beds are also the place for sex. Extensive studies have shown that 0.033 per cent of the time spent in bed is for sex. Otherwise, the rest of the time is split evenly between dreaming about sex and having nightmares about sex. Since most of those dreams or nightmares involve dogs, they are often considered to be man's best friend by your run-of-the-mill perv.