Years ago, while plumbing the 727 (the first time), I was going to check the cargo door locks, before closing the jet up to go fly. When I got to the top of the stairs, the mechanic, who I just observed, was checking the locks, looked up at me and gave me a thumbs "up" sign, and mouthed the words, "the locks are good." I then closed the main hatchway door and installed the girt bar. When I got into the cockpit, the captain (who had been watching me from his L1 window) asked if I had checked the locks. I told him the mechanic did and so I didn't. He told me it was my job (no argument there) and to go and do it. Long story short, by the time the crew stairs were put back in place, and I had checked the locks, climbed back into the jet, and reclosed the entry door, reinstalled the girt bar, and was back in my seat, was about 6 minutes. That sir, is a crew delay. Going direct, rather than flying the flight plan, and running into unanticipated headwinds, that cause you to land late, is another example of a crew delay. Taxiing to the wrong gate, and having to "go around" to get to the proper gate, is another. There's plenty of chances to create a crew delay, and thankfully the vast majority of our pilots, for whatever reason, always seem to avoid them. But none are immune to having one on almost any flight. The shame of the system, in my opinion, is that they've taken a large amount of delay codes out of the system, so that when we go to report these delays, we are limited to things like: taxi out delay; weather enroute; taxi in delay; fouled gate; and my all time favorite, ATC delay.