Exactly make a few huge mistakes, you start sweating you feel so awkward. All you can think after all is said and done:
"I'm never going to let that happen again "
It only happens live, not in the bedroom.
...and that leads to the answer to the question for a lot of people, whether they admit it or not: Fear of hitting the wrong note, forgetting a passage, looking weird... collectively known as stage fright.
Oh, and... Go Big Blue.
This seems to be problematic considering many musicians are self-taught and often don't practice many fundamentals. Some take lessons, but the quality of guitar and bass instructors can vary widely. Some are classically trained and others are self-taught, passing on their bad habits to others.