Hehe.. It's funny to read all those interesting remarks.
Over here in Norway most grocery stores have been doing this for more than 10 years now, and I have to say you get used to it.
Of course the purpose is to encourage people to bring their own bags and reuse them, but both you and I knows that this won't happen because most of us shop spontaneously and are therefore not carrying a bag at all times.
On the other hand I think the western world is obliged to do something with our overflow of everything - also plastic garbage, so I kind of support putting a fee on plastic bags. But USD 0,25 seems a little bit high. the fee over here is something around 0.15.