Kevin's current post The world inside a coconut contains a most wonderful description of why he fell in love with what he does. Kevin tells of doing scut work on a research boat and when the samples come up:
I also found my passion was sorting through rocks, sediment, snot, you name it and finding critters. I seemed to be very good at it as the Chief P.I. and other biologists seemed pretty please with my findings! Sorting is still something I take great pleasure in. I get all giggly when a box full of crap comes up from the seafloor, filled with various worms, gastropods, amphipods... its the "what new thing might I find if I keep looking?" that keeps my interests peaked.