I know that the way I have been treating that picture (see the last month of posts, or so) is wrong. Or, at least, it's wrong from some perspectives.
A picture with energy, which is generally a picture that conveys a sense of being drawn with confidence and economy, is better than a picture which is more accurate or realistic, but doesn't have the energy. Working on a picture continuously, tweaking, is a great way to kill energy. This is why the sketch, waaay back, although it has some problems, is a better picture.
Also, by working on the same picture for a long time I am losing opportunities to practice. I'm getting rusty, I suspect.
So why do I keep at it? Sheer bloodymindedness is part of it. I'm not fond of giving up until I've done the best I feel I can do. I'm learning, too, especially with the color stuff.
About comments: I love getting comments. I admit, being told a picture looks good is a real motivator. I may not always agree that the picture in question looks good, but that's because I'm criticizing, not appreciating. Sitting back and admiring my own work is not conducive to getting the job done, but being reminded that maybe not everyone is so critical does wonders. Keeps me from stabbing my own eyes out with a stylus, sometimes.
Critical comments are good, too. I won't lie and say criticism doesn't sting at all, but it's important (very important) to be able to get past that sting and evaluate critical comments. Advice, even if I chose not to take it, always offers a new perspective.