It can turn the most positive, outgoing people into shy, depressed people dependant on drugs or vice versa. Passion, focus and persistence are three of the most consistently recognised factors in successful people. Persistence - The number of very successful bands that were initially rejected by virtually all and sundry are there for all to see, the Beatles being the most widely recognised, Savage Garden one of the most recent. They do so in the face of injury, public and private pressures, form slumps etc. To succeed they keep perservering until their day comes.
Passion is something most people have from time to time - it is merely a matter of harnessing it.
If you have the passion for music, use that passion to spend time developing your performing ability, knowledge of how the business works, song-writing skills, bank account, network of people etc. Everyone is human and gets depressed, upset, angry, frustrated, but it is how you react to and use these things that separates achievers and the norm. When things are tough, focus keeps you heading in a certain direction. No matter how large the dreams are, they are obtainable in some degree or fashion. Sure you may not get that multi-million dollar bank account, but your life will be far richer for trying.