I was at BWI Airport 12/9/10 to fly to Charlotte, NC Flight 1029. I went to the baggage check-in and this was my first time with the computer credit card screen. I said to the employee (Tom B.) 10:00 AM that I wanted to check my luggage in and he sarcastically said that is what everyone here is doing and walked away from me. I did not know what to do. A woman who was a passenger proceeded and told me what to do. I was so grateful to her. This employee upset me very much.