I have flown a lot, both domestically and international flights. The WORST AIRLINE BY FAR, and my worst experience was flying with United. I was trying to fly from Dallas Ft. Worth to Vancouver, B.C. My first flight, connecting through O'Hare was delayed by three hours because of a snow storm in Chicago. I was afraid I would miss my connection, however the gate agents would not talk to me, and kept referring me to a telephon system. When I spoke to agents via telephone, they assured me because everything was also delayed at O'Hare, I most likely would not miss my connection. Cut a long story short, I arrived at O'Hare to a completely deserted airport, my flights had been rebooked for the morning, and at no time did I actually interact with a human during this entire process, it was with machines and telephones. The final straw though, is when I finally landed in Vancouver. I ended up collapsing at the Canada Customs counter. Apparently during my flights, I developed a blood clot in my leg, that had travelled to my lungs. It was very close to moving into my heart, and could have killed me. I e