It sounds like you're the type of person to blame external factors for your own issues. Nothing you're saying counters the original advice.
Additionally, in the guitar example, you learned how to play and learned what it meant to own a decent guitar. Then, when presented with the opportunity to buy a new guitar: bought a crappy one, ignoring everything you had already learned about the instrument.
Given that you were so easily discouraged from learning the guitar, it's also equally likely that it wasn't something you were truly passionate about and gave yourself an excuse at every turn as to why you weren't progressing.
Additionally, in the guitar example, you learned how to play and learned what it meant to own a decent guitar. Then, when presented with the opportunity to buy a new guitar: bought a crappy one, ignoring everything you had already learned about the instrument.
Given that you were so easily discouraged from learning the guitar, it's also equally likely that it wasn't something you were truly passionate about and gave yourself an excuse at every turn as to why you weren't progressing.