Senseless waste of precious time...
1)Kittens. Self-explanatory.
2)Kisses. Again, self-explanatory.
3)King size chocolate bars. Some to eat, some to save for later.
4)Kinkyness. Probably self-explanatory.
5)Karma. It would be nice if it actually existed...
6)Kool-Aid. Who the hell doesn't love Kool-Aid?
7)Kindness. I like the Devil's Dictionary definition of it, it fits the vast majority of people.
8)Kinetic energy. It's fun to move. I'm running out of words that start with K, can you tell?
9)Ketchup. A small amount on fries is yummy.
10)Kareoke. Watching people make asses out of themselves is always a good time!