I agree, there have been times I learn a new method and wish I had known that years ago! Or at work, I see someone do something with excel and I say "stop, how did you just do that?"
Now days, there is so much informational videos online (and yes, even for excel) and forums to ask. Then you have to wade through it all and decide what you want to try and what you don't care for.
And not all techniques work for everyone, and without some talent, practice will only get you so far.
I'm the type that takes continuous improvement to heart. I'm always looking for new ideas and processes to see if I can incorporate them into my current ones. But then I also have to keep up on 30 hours of continuing education so I'm use to learning and implementing new things.
For sewing, I know when I'm struggling. I don't delude myself that it's "wonderful" when it's not. Knowing yourself goes a long way to improvement. I've worked with many that honestly have no clue that they are mediocre. They are hard workers and doing their best, but their best is C+ to B- work. And no matter how much I work with them, they will never be able to do A work in that field. They are the ones I counsel to find a different career, something much more suited to their talents.
If you have an honest desire to improve, you are well on your way. There is nothing wrong with getting to a point of proficiency and deciding that is where you want to stay, but if you want to improve, you need to be able to look at your work and see where the problems are.
My number one complaint with this board is the tendency to be a feel good group, it's very hard to get constructive criticism, and even if someone asked, you'll still get way too many "it's good enough, why worry?" comments, especially when it's very obvious that the person has a ton of room for improvement. I sometimes think this board is best if you want to feel good about being mediocre. If you don't feel what you did is all that great, post a picture and say "I'm not sure if this is good enough" and you'll get 95 responses telling you how wonderful it is and don't worry about it. And if someone posts about where they can improve, others will jump on them for being "quilt police" or mean. Hard to learn how to improve when others are afraid to offer help.
I have visited one garment sewing board where they have a section specifically for critique. And it says at the top not to post pictures there unless you want it picked apart and areas for improvement pointed out. Very educational, and those that offer advice are quite knowledgeable. I've yet to find a place like that for quilting.