Dear Sir, What If I...

Do you regret your choices? Would you throw away your potential? Yusuke Hinata is the guitarist of a boring trio band.
A rock band is supposed to perform hip songs with a spectacular stage after a few years, but they've only performed at small local events after all these years.
I thought my guitar was all that I had to offer and crossed out other options, but was that the right decision...?
A classmate who had formed a band, they called out, who was it?