MagSafe car adapter
As you probably know, the MagSafe adapter is a great invention. Someone trips over your power cord, and the connector pops off.
And if you think “well, cool, but won’t happen, a normal connector won’t break your notebook” you’re very wrong.
A few months ago, at school, during courses, someone tripped over my Powerbook’s power cord, and pulled everything off the table. This resulted in complete data loss + broken adapter + banana-looking case; 926 EUR repairing costs (Yes, this is when I dediced the get myself a Macbook (Pro), and the good thing was that Leopard was about to be released).