Penny for My Thoughts?

What's with businesses that are sticklers for an extra penny? I was in the Pru on Friday night, and as usual, I decided to grab some dinner from Poulet Rotisserie Chicken because I always figure that of all the options in the food court, this will be the healthiest. (Or, more accurately, it's just good food.)

I got what I usually do: the combo platter (i.e.: a main dish and two sides — on Friday, that meant basic chicken tenders, mac'n'cheese and steamed vegetables) and a drink. As always, the bill came to $9.01. Now, aside from how wrong it is to pay so much for fast (albeit good) food, the place demands that you pay exactly $9.01. There have been times that I've been to Poulet and have paid with a $10 bill and have received 99 cents back as change. And when I've tried to pay just $9 (because I either had no change on me or just had, like, a quarter), I've been asked for the penny as if I was robbing them blind. There's no "Have a Penny, Leave a Penny" dish, and after all this time, the place still hasn't adjusted their prices so people's bills are exactly $9, or so they're at least closer to the other side of $9 (i.e.: $8.90-something).

Yes, I'm a sucker for always going back there even though this really annoys me, and I was just lucky I had a penny on me Friday night. But really, what's with them making me (and everyone else) pay exactly $9.01? Why can't they just let us pay $9 and be done with it?