I've worn both hats professionally. In the years of my heavy jet and GA wrenching, I enjoyed it, fixed it right the first time, and did my best to help an on-time departure. Troops were waiting for stuff on this plane, and I took it personal to get it fixed and on the way. 2am, on top of a 65 foot t-tail, in the rain, safety wiring a bolt, was miserable. Get the job done and see your work take flight, that was instant gratification.
But that's about where the gratification comes to a stop. It is extremely rare for a mechanic to be recognized for their efforts. How many times has a Captain, Aircraft Commander, or senior officer come back afterwards to Joe Wrench and thanked him, acknowledged his effort, or wrote a commendation letter to his supervisor. An extremely rare event. Often times, the flight crew is pushy to get the mechanic to sign the paperwork, get off the flight deck, and not get grease smudges on the seats.
And so young chipper Joe Wrench goes through this cycle. Hurry up, do a perfect job, get out of the way. Get pulled from job to job as priority changes. Respond to often vague or un-repeatable write-ups made by pilots who don't fully understand the normal system operation. Get your pension taken away. Have your union dues increase. Buy new tools. Get assigned more extra duties. It doesn't take long before young and chipper can get worn down. Who wouldn't become that way? A highly experienced A&P rarely, rarely receives the social accolades as would a similarly experienced pilot.
As I wear the other hat now, I'm reminded of my beginnings every time a write up goes in the books. I see things from the other side that resonate as they did not before. What gets me the most is the penchant for mechanics to do the minimum. There seems to be the overall tendency to defer to the maximum of the MEL limits, rather than to get something fixed. It often falls on the Captain to outright refuse an airplane in order to get something worked on, often having to battle a mx supervisor about the delay code. It creates hostility, and is poor service to our customers. What gets even more frustrating is when I know something is obviously wrong, come out after maintenance has worked on it, only to find half-assed troubleshooting, could not duplicate, "within limits", and even the almighty pencil whip. Oh, on your walkaround you found a blown strut with black fluid running down the chrome? Wipe it down with dirty rag, a shot of compressed air (not even nitrogen), and you're good to go sir. That stuff floors me, and has happened to me. "You're a pilot, not a mechanic, who are you to say what's good and what's not?" It gets to be a hardball game at that point, a game that just raises tensions.
I expect an A&P to see the bigger picture and keep the metal flying, and also to have the fortitude to stop the show and take the delay hit when it is necessary. If they are making the right call, they should be backed up by their superiors as well as the flight crew. I also expect the guys and gals I share a flight deck with to know the systems well enough to avoid stupid and wasteful write-ups. Perhaps I'm too much of an optimist, but if there is decent respect for the other guys job, the culture between the two is often much better.
The 121 world is much more time focused than GA. I've been out on the line and I've been in MCC, so I know how both sides see it. MCC is pressured to minimize ground time and not screw up the schedule too much.. MCC in turn pressures the line mechanics to fix or MEL the problem as quickly as possible. A lot of time line maintenance pushes back and needs more time. There just isn't a lot of troubleshooting time in between flights, so that's when they just throw parts at the problem to see what works and fixes the problem. If it's a deferral item, it gets deferred or continues on MEL. My A&P will payoff in dividends when it comes time to fly professionally and have to go through systems during training! 
