STL-PHL r/t, 813 miles of pure hell.
Going there wasn't so bad, but on the way back, I guess we encountered some strong headwinds and the flight was about 3 hours. If it were up to me, I would've taken Southwest since they do STL-PHL nonstop, but it was booked for me by corporate travel without any input from me. Hell, I would've rather had a stop somewhere if both segments would've been mainline.
STL doesn't have much in the way of mainline service anymore, but fortunately, ORD is close enough that I can tolerate a short RJ flight to that and switch to mainline.