The human relationship

I think it's quite difficult to keep the relationship good among band members. I don't mean to hate my friend who doesn't follow me. We need to discuss and talk each other. We have to get rid of a distrust. The dawn of misunderstanding is just like this. One of members didn't prepare
the harmonica which he had to play in The Sun Francisco Bay Blues. I repeatedly asked him buy that stuff, but he didn't . I was really disappointed this time. Do you think I am right or not?