Four equally qualified applicants interview for a job position...

...and the interviewer says to them all, "I'm glad you have all made it this far, and honestly I didn't expect all four of you to impress me as much as each of you did. However, you can't all get the job. This final interview will decide who gets the job. I will ask you all the same question, and whoever has the best response gets the job."

All of the applicants look at each other and then back at the interviewer. With one final nod to all four of them, he begins the final interview.

"Your final question is..." the interviewer says, "...what is the fastest thing in the universe?"

The first applicant sat for no more than a minute to think about his answer. Finally he says, "A thought! We have thousands a day, and they are so quick, you don't even realize that you are thinking about something sometimes."

The interviewer repeats the question to the next person.

The second applicant, after short deliberation, says, "A blink! Much like thoughts, we have several thousand per day and we barely recognize its happening. It has to be so quick that it can stop anything from harming your eye in an instant."

The interviewer repeats the question to the next person.

The third applicant says confidently, "Light. The speed of light it so fast that humans literally cannot reach it ever. It's hard to even fathom the speed of light, but it when you walk into a room and flick on a light it seems instantaneous."

The interviewer, very impressed by the level of thought that each of the applicants has given with their responses, turns to the final applicant and says, "Well, what do you think is the fastest thing in the universe?"

Almost immediately the fourth applicant says, "Diharrea."

Confused and taken aback, the interviewer says, "Well I don't know what you could possibly mean by that, but do you care to explain yourself?"

The final applicant nods and explains, "Diharrea is the quickest thing in the universe because before you can even think, blink, or turn on a fuckin' light, you've already shit your pants."