Gate M For “Malicious”

(I am going on my first international trip and I have a layover at O’Hare airport in Chicago. I’ve never been there before and the airport is MASSIVE. I get off my flight at terminal 2 and see that my next ticket says Gate M12, but I can’t figure out where the M gates are. I ask the first person I can find, who happens to be a TSA agent. )

Me: “Hi! Can you please tell me how to get to the M gates?”

Agent: “Terminal 5.”

(She stares at me, so I start to look around for signs pointing to terminal 5 and see nothing. I look back at her again.) 

Me: “Could you please tell me how to get to terminal 5?”

Agent: *in an extremely condescending tone* “Are you ready to listen or are you going to keep looking around?” 

(Thankfully, her directions were clear, but I have no idea what I did to get so much attitude.)