Take skydiving, for example. As a beginner, you're keenly aware that every time you toss yourself out of a plane, you're committing suicide, and every time, the parachute saves your life. Quite quickly, it can be easy to equate "wearing a parachute" to "nothing will go wrong".
A skydive rig is an incredible feat of engineering. Each fold and stitch has a history, a reason and a purpose. It's a thing of beauty. However, in a skydive rig, half the system is a black box: You're not allowed to touch or handle the reserve part. This can foster a complacency, or a shift of responsibility: It doesn't matter if my pack was terrible, I've got my reserve..
Checklists do exist: In theory you'll check your AAD (Automatic Activation Device - it basically fires your reserve if you haven't opened by a certain altitude), your pins (reserve and main), your handles (pilot chute / main handle, cut-away handle, reserve handle), straps (leg straps, chest strap), ring system (RSL and three ring system), and then your own gear (helmet, goggles, alti).
However, expectation of performance (IE, every time you've worn your chute it's worked, leads to complacency), peer pressure (it's totally 'not cool' for experienced jumpers to ask for a gear check) - rushing - and the 'laid back' environment of dropzones erode the seriousness of the task and the importance of stringent checking.