hour sitting on the ground in December. No one wanted to show up to work, and this was a mid-morning flight. (Shops were shuttered too - no KinderEggs this year.) Then it was de-icing personnel. We sat, on the plane, for 2:50, before we pushed back from the gate. Missed my connection on US East Coast (Newark - what a lousy airport - a cold sandwich from a refrigerator was cheapest food available, for $15), and was 6 hour later getting home than planned. (Lufthansa flight/United ticketing.)

Loads more I could say about Frankfurt, but that would be all negatives, and not keeping with the OP.