A recent episode of "Revolution" covered one of my fears: being tricked into solving a code problem through a dream.
After I watched "Inception" it was clear to me that the real value wouldn't be tricking an executive into revealing some small memorized thing, or even introducing an idea. No way! A skilled consultant costs hundreds of dollars an hour. Because time is accelerated in the dream, you could get days of work out of a consultant, overnight. Ideally there would be a friendly agreement between the consultant and the business, and there would be a light workload and luxurious benefits at no cost. But I could easily see it turning into a sweatshop condition, or an intense training simulation, or like in Revolution/Inception the dream challenge could be dumped on you.
So that's one of my metaphysical fears. Here are some more equally illogical, but nasty ones: