Prior to tonight, I'd had several great experiences at Mac Shack. Tonight ruined any chance of my return to the restaurant. The young lady working the register told me that the owner will not allow any substitutions or changes in their "pre-packaged" pasta dishes. When I asked why, as I'd had it done before without any argument from the staff, she walked away and got another young man to come over and tell me that the owner used to allow it, but now really doesn't like it and they can't do it. When I told them that I'd just find somewhere else to eat (and I did), NEITHER of them made any effort to retain my business. It's not like I was asking to add ingredients to a dish without being charged or cheat the system - I just don't like shrimp or jalapenos in my pasta, but LOVE the rest of the dish. I didn't think it would be too difficult to accommodate a simple request like substituting one vegetable for another, but hey, what do I know!? I wouldn't be shocked if other loyal, regular customers find elsewhere to dine as well. Disappointing, really.