Oooh - and excuse for long-winded and rambling reminisce-age!
I've had a few engineering "careers" over the last 30 years. They change from time to time, and with each new one comes new highs and lows.
[The early years]
After getting an AAS in electronics, I started out as an R&D technician with Dupont and worked my way up there until I was running mid-sized projects developing lab automation for Ag research. I highlighted that part of my life in another thread
What would be your dream tech job?.
In that phase of my career, the high point had to be when I was working on a fast-track new venture team developing a portable medical device for making sterile tubing connections for peritoneal dialysis patients. If successful, this device would free these patients from having to manually make the connections to change dialysis bags - a big source of infection and which severely limited their freedom and quality of life.
The engineering of this device was a real challenge. The prototypes had to be as nearly fail-safe as possible, no bigger than a shoe box, economically manufacturable and pass clinical field trials with real patients. This project used materials and techniques which we take for granted today, but were pretty new at the time: embedded control (Intel's 8085 single-chip uP) and high-performance engineering plastics like Delrin and Torlon. I was responsible for the control system hardware design and fabrication.
We had to deal with a lot of issues like electrostatic discharge which caused the uP to lock up, getting good temperature control of the heated blade (which cut and welded the tube ends together) using just the temperature cooefficient of resistance as an indicator, making the instrument frame rigid enough to hold everything in critical alignment and keeping the weight manageable for semi-invalids.
After exhaustive in-house testing we got the first of these "Sterile Connection Devices" (product naming was never Dupont's strong suit) out into clinical trials and held our breath. The patients love it! It made it possible for them to get out of the house, take walks and do things with their families which they'd been afraid to do for fear of not having a place to make a sterile bag change.
Probably
the high point of my engineering career came when we released the second-generation prototype SCD and some of the patients who had the first ones refused to bring them back - they loved them that much. We also got some interesting stories back from the clinicians, like the one about one patient who had a pet duck which always sat in his lap while he made the bag change.
The low point of my career was on the same project when the company decided not to go forward with the product because of fears over liability in the case a connection went awry. We were devastated, not just as engineers, but knowing how much we had improved the patients' quality of life, and that they would have to go back to the risky manual methods which chained them to home - and almost guaranteed they would suffer peritonitis eventually.
[many years pass]
When Dupont started downsizing R&D in the 90's I took a chance and a position as senior systems engineer at fledgling Pharmacopeia - a pharmaceutical research start-up in Princeton, NJ. The company was less than a year old, and I was in the first wave of staffing up to complete their "proof of principle" which we hoped would attract big pharma to collaborate and convince venture capitalists to increase their funding.
My job description was pretty general - the company philosophy was "if it isn't chemistry or biology, it must be engineering". The corollary to that was, if it is chemistry or biology, but you have to do it a lot, it must be engineering, too. So, I got to learn a little about a lot of subjects, from analytical chemistry to high-throughput biochemical screening, and figure out how to make them work better, faster and cheaper for us. Among many accomplishments I got a couple of patents for methods of rapidly drying sensitive chemical samples without oxidative or thermal degradation, and designed photochemical cleavage systems. Recall my degree is in electronics, so you can see how far I moved and how much I had to learn.
The high point of this part of my career was probably being told by the leader of one group that if he had an engineering problem that wasn't real critical he'd give it to the manager of the engineering group to assign, but if it absolutely had to be solved he'd come to me first. The low point began when they hired that engineering manager - giving me the line that my work was too important for me to be distracted by managing a group. I butted heads with that fellow for many years, but eventually he was let go and I replaced him.
[fast-forward to present]
These days I spend less than 10% of my time on hardware engineering, about a third of my time on management stuff and half my time on safety. One great thing about working in a small company is you get to wear a lot of hats. The big problem with working in a small company is you have to wear the hats, even if they keep you away from what you were hired for. Not that I don't feel safety is critical to the health and productivity of the employees and the company (I did work at Dupont, after all) - it's just that managing environmental, health and safety is crushingly boring and stressful for me.
Oh, and one of the high points of my recent career is seeing the narrowly-focused software engineer whom I mentor take on new roles and responsibilities. The other day he came to me complaining that an outside engineering company had over-tightened the conveyor belts on one of our instruments and he'd had to re-adjust 11 of them. The "old" software engineer wouldn't have checked the belts, let alone adjust them - he'd have "fixed" the problem in software and the bearings would have failed prematurely. Now he takes a broader view, tracked down the problem before it became a big one, determined the extent of it and fixed it himself. Like I said, you have to wear a lot of hats and Alex is developing a nice collection of his own.