Laptops shock barefoot users

The other day I was typing on my MacBook Pro when suddenly I felt a sharp pain on my wrist. I got a huge fright, but I didn't know what it was so I just carried on typing. Then it happened again, and when I cautiously touched the casing of my Mac with my hand, I felt an uncomfortable tingle.

I did a search on Google to find out why my Mac was suddenly emitting shocks, and found many results not only for MacBooks but other laptops as well. They were all complaining about getting shocked while their laptops were charging - apparently it's a common problem with the grounding, and can be fixed by using a grounded plug.

But I was only getting shocked when my MacBook wasn't charging. I wondered what I was doing that day that was different from every other day I had used my Mac and never got shocked, and then I realized it - I was barefoot! Sure enough, if I lift my feet off the ground and touch my Mac I don't get shocked, and if I put them down again - zap! Click here to read a forum thread in which this problem is discussed.

I bought my Mac in the winter and have been wearing shoes all the time, so I only noticed the shocks now that it's summer and I go barefoot around the house. My Mac could have had this problem since the beginning :(

Does anyone else have the same problem?

P.S. If you're wondering why my little vetor portrait is a bit on the grey side, that's supposed to be ash from the "electrocution" :P