2. It is immensely irritating when, just as you are about to buy the raw materials with which to power all your cities and win the game, your opponent (who was buying raw materials first) reaches over and calmly buys one more unit of coal than they actually need, leaving you one short. ;)
3. Trying to run a mail system which includes a whitelist of 180,000 email addresses is a really bad idea. Unless you like watching Sendmail and SpamAssassin waltzing together in treacle, that is.