Just some thoughts I put together. . .
The busiest trainer at your gym and the best trainer at your gym are probably not the same person. One spends their time improving their marketing skills, the other their training skills. Pick the right one.
When you want to improve at something do not look for a coach who is naturally good at that thing. Find the coach who has little natural talent but developed through perseverance, determination and skill. That's the coach who knows all the tricks to help you improve, the naturally gifted individual never had to struggle for success so they really don't know how to achieve it outside of having the right genetics.
In the end if you want to get better at something practice!!! If you want to be better at throwing a baseball you go out and throw a baseball, you don't spend hours in the gym doing internal rotation work. If you want to get better at lifting heavy weights go lift heavy weights, anything else is a detail that can be added later.
If a muscle won't grow don't worry about it, instead try and make it stronger. One of the adaptations that your body will undergo to increase strength is hypertrophy. While it may not be the most efficient way it's never failed anyone yet.
If you can't bench 1.5 x your bodyweight, deadlift 2x your bodyweight and squat 2x your bodyweight you don't have sticking points, you're weak.
Not everyone shares your goals, while we may not understand the mind of a marathon runner we should not mock them. They may not want what we want but their dedication is without question, the same goes for any athlete, powerlifter or bodybuilder.
When people ask you to help them improve themselves take them seriously, if they've gone through the effort of asking for help it's the least you can do.
If someone asks for help improving themselves tell them to keep a diet log for 2 weeks then come back and talk to you. If they do it they obviously have what it takes to make the changes, if they don't you'll never see them again.
Too often in sports coaches organize their practices by mimicking what their coaches had them do, there's no rational or thought given to it. If a coach can't hold at least a moderately informed discussion on the physiological, psychological, or technical benefits of what they tell you to do then find another coach. "It'll get you in shape" is not a valid answer.
If you ask someone for advice because they know more than you ensure you take their advice. Don't start changing things because you want to, experts have a reason for everything they tell you to do and this is why you went to them, don't mess with it.
Your ego is not a good training partner, leave it at home.