Do you feel the same way?
Not anymore. I did and do about code I wrote when I first started. But I like my code now.
If so, then what is holding you back from realizing your full potential?
I learned design patterns and how to implement them. That's what's made me a better programmer.
Have any developers here successfully lobbied their company to stop or cut back on 'cowboy coding' and adopt best practices?
No because most non-programmers don't agree with the business value in it. But, implementing design patterns to solve my problems helps enormously.
Has anyone convinced their superiors that the customer isn't always right and saying no once in awhile is the best course of action?
No. Cuz the person with the money is always right, or they'll pay someone else to do it.