The major problem with going into the "Arts" is that there is no guarantee that you can make a good living doing it. Whether you practice six hours a day, get a doctorate from a renowned institution, or studying with the best teachers and coaches in the world, there is nothing that guarantees you can earn a living doing it. It just isn't fair.
You can do all of the right things, the right way, and cross every T and dot every i and still not establish a career that supports even the lowest standard of living. You can be a great colleague or a total pain and it doesn't matter. There is no justice in it.
Whether you "make it" or not is something you have no control over. So stop beating yourself up when you don't make it as you'd like.
It is easy to get bitter about the lack of success in your career when you have worked so hard to be good enough to do it at all. I've heard all of the arguments placing blame on others when there is actually no blame to be dealt.
Quotes like, "They don't know what they are talking about." "That theater is just full of awful people." "People just don't get me." "The agents have all of the jobs tied up." So it is easy to bad mouth everything when you don't make it.
It doesn't mean you are bad, untalented, or not deserving. There is no reason for it.
It isn't a fun thing at all.