I think Tog wanders away from the "design bugs" topic but here's his list:

- Identical controls used for asymmetrical weapons systems, with insufficient mode feedback.

- If the computer loses power for more than a few thousandths of a second, it throws everything away.

- Nine separate and distinct design bugs in the OSX Dock.

- Designers offer no way for users to discover why a given menu or option has been dimmed (grayed out), nor how to turn it back on.

- 15 Dec 2008 sorts as being before 2 Jan 1900.

- Many browsers disallow entry of spaces & other normal human-language characters into web addresses. The rest do inappropriate things with them.

- Weird formats for standardized data.

- ecommerce sites are making it as difficult to buy products as humanly possible.

- "Smart" functions often make the wrong decisions.

- Focus stealing.

"ecommerce sites are making it as difficult to buy products as humanly possible."

If my credit card has a number as four blocks of four digits then I expect to type four blocks of four digits. A webpage with <input limit=16> is wrong. This was easy to fix in 1998 and it is trivial to fix, client side and server side, in 2008. This isn't academic. This increases support and it costs sales.

If I encounter this case then I take business elsewhere. If they cannot get this issue right then how I trust that they'll fulfil my order? I'm not being petty but if this issue is apparent then testing isn't sufficient and they're not acting on feedback. In either case, this is evidence that they're less likely to send the correct products first time, less likely to fix mistakes and less likely to give a refund.