LOL, a secret life. Nah, I have an account from which I all normal transactions (get my wages, pay bills etc.) and one savings account. And whenever I got something left on the normal one I transfer it to the other.
The problem with cheques is, that one has to wait for them to clear. Not good if you want to pay the car and drive home. Sometimes even new cars get paid in cash because the dealer gives you an incentive for doing so - so he doesn´t have to pay commission to some credit card firm.
Other businesses that don´t regularly accept cash are travel agents and retailers, again because of the commission. Buying a TV or air ticket in cash is not that uncommon. The use of plastic money is simply less wide spread on this side of the pond. The credit card CEOs are probably pissed - such a great market potential, and these dumb stone age Europeans continue stubbornly to pay cash...
And finally, maybe us Europeans have a little psychological problem: the fear of war and/or having to flee is deeply rooted especially in older citizens. Maybe that causes our fondness towards cash in general and large denominations in particular.
The BEP website Ihadapheo mentioned is really great. It has pictures of all the notes. They call the 100,000 a "gold certificate which cannot be legally owned by private persons" (not an exact quote). I guess one can´t call that a banknote in the true sense.
I found one of the educational fivers Ihadapheo fancies is currently at eBay:
It´s at 7100 US$ right now, and the reserve price isn´t even met yet.