We were delayed due a mechanical issue after we were boarded. It is not a good thing to keep folks squished in economy fare seats longer that the intended flight! It cost many passengers, including me, their connecting flights. My mother was ill and spending six hours in a layer over that was unplanned did not leave a good taste in my mouth. This was the second time mechanical issues with Delta kept me on the plane and miss my connection. Maybe they need to take time out to fix these older planes???