Oddly enough, low time pilots often have to deal with more mechanicals than high time. Here's why. Low time guys are usually droning about in minimally maintained pistons, while the high-timers are often in turbines that are professionally maintained. Turbine reliability is simply awesome. In 22 years of turbine flying, I've shut exactly one engine down as a precaution, and have had VERY few other problems mechanically.
Weather and international ops is the difference, I think. After enough flying, you'll think you have encountered every possible weather phenomenon, yet every year, you add another to your plate. Stuff like grinding, turbulent rain at a non-radar mountanous airport where the controllers have lied - LIED - to you about the vis so his local boys can operate; CATIII RVR vis so thin vertically that the airplane begins its flare at 40 feet and you are still in the clear above the WX, then the jet autolands into the goo. Within 2 seconds you go from VFR on top, to touchdown into SMGS taxi guidance.
Stuff like North Atlantic Track procedures, working HF with Shanwick or Gander, trying to avoid WX and watching the icebergs pass by; calculating SE driftdown over Greenland so if it happens, the passengers will not run out of O2 at 17,000'.
The experiences keep piling up, and you realize that you didn't know squat before, and you'll never know it all, and the number of things out there that can kill you, and all your passengers, are infinite. Respect grows and you become cautious.
