The clock at work hates me

So I was at work today and before lunch I noticed that the clock was 5 minutes slow. So I set the clock to the right time and I go to lunch. when I get back to the office, the clock is 5 minutes fast! Ok, now I'm thinking that someone is playing bad joke on me or the clock really just hates me. Seeing as how I was the first person back to the office (and everyone else is too lazy to play a joke, I can only assume that the clock does infact hate me. So now I'm looking for ways to exorcise the demons out of the clock.