1. Sometimes they go up
    This generally makes people very happy. It also doesn't really affect me personally, so who cares, people.
  2. Sometimes they go down
    This usually makes people sad or angry I believe. Again, doesn't affect me noticably, so I don't lose any sleep over it.
  3. You can't buy just one
    I once spent an afternoon trying to buy a single stock so I would have something to watch go up and down. It turns out that this isn't a service offered by any stock trading websites, not even the one with the talking baby in the commercial
  4. The Dow Jones
    I think this guy owns all the stocks? I'm not sure about this one.
  5. If you broke the rules in olden days, they'd put you in the stocks
    Different stocks for sure, but the concept still applies.
  6. Getting a job as a stock boy wasn't what I expected
    I didn't know which definition of "stock" it was going to be, and it turned out to be the worst one.
  7. Something happened with the stocks today!
    See "sometimes they go down"