Last time I did TOL-DTW we were:
--boarded and sat at the gate for an hour (tstorms)
--pushed back and held on the tarmac for an add'l hour (flow)
--finally cleared and put in the air...only to be put in a hold (!) for 45 mins (ATC)
--Landed, then there was a computer failure inside the terminal...and no a/c could park at a gate. 1 hour more on the taxiway sitting right outside the B gates.

Total time, TOL-DTW: approx 4 hrs 15 mins.

Yeesh.