Ron McGovney, Metallica's original bassist, was never a good fit for the band. While he was good friends with James Hetfield, he rarely got along with Lars and even more rarely with Dave Mustaine, the band's original guitarist. They seemingly looked at him as nothing but a money man. According to McGovney in an interview with Shockwaves, he was the one who paid for just about everything; gas, trailers, hotels, and everything else went on his card. When he complained about this, they apparently just laughed at him and said he needed a sense of humor. Going broke is hilarious!
Plus, while McGovney was a serviceable bass player, the band was seemingly always looking to replace him. They found that opportunity when they attended a Trauma show and found themselves blown away by their bassist, Cliff Burton. Almost immediately, and behind McGovney's back, the band sought to hire Cliff and either fire Ron or treat him terribly until he quit. They mocked him, treated him like an outcast, stole his stuff and—in what appears to have been the final straw—poured beer into his amp so it wouldn't work. That incident was enough for Ron to kick the entire band out of his house, which they reacted to by moving to another city with Cliff, leaving Ron behind with shattered gear and shattered dreams.