Anyone know what AA2214 (N819NN) on 6/8 was in maintenance for, last recorded flight prior was 6/5? Pure guess, but wondering if it was engine blade inspection, as each blade had a handwritten number on it. First delay was 10 minutes to get the plane over, as the prior departure was a bit late. This became a bad joke as every 15 minutes it delayed another 15 minutes until the plane arrived. Crew boards, expecting to board in 10-15 minutes, which passes, and another 20 minutes slip. MX after being in the shop overnight, can't turn the cabin lights on. Once on, screens don't come down for the safety video, more work, screens finally drop, at least we didn't have to go back to have someone sort that out. Ultimately, 2 hours late. They had the food cart out at DTW, sitting at DFW, we got nothing other than a false start boarding, then getting waved off.