Today's 6:10a SFO-MSP flight DL 2806 changed to a 5:55a departure. What's that all about? That's a first for me. Apparently everyone got the same wake-up call at 3:30am. Everyone that is except the cabin crew. Captain said "we just wanted to get you to MSP early today". Right and fat chance of that since we went mechanical on the taxiway, returned to the gate and finally departed at 7:30a. Adding to my wonderful day, DL has just cancelled my connecting flight, even though we are picking up time and are now scheduled to arrive MSP at T-30.