So why do people still write checks in grocery stores?

I guess this has been discussed alot in several blogs, but I just don't get it.
How come people still feel the need to delay the people behind them, take the effort to fill out all the fields on a check and the check register... when they could use a check card and be done with it? Quicker, easier, and actually costs less?

Adding up the time and printing costs of checks... they don't make sense anymore.
ATM/check cards don't charge a fee, although "credit" cards do, in interest and in "processing fees" to the merchant. But ATM/check cards are free... what's the deal? nostalgia? Anybody have any insights here?

Charlie