Did i HELP or INSULT my boss ?

I work like waiters in a disco place.Boss and i we are friends.I mean we know each other well and i trust to tell him thinks that i don t tell to anyone.He its not so open with me but i think cos its bec of his statute...We have also our manager in there.My boss help me and i was thinking cos i will return the help telling him what our costumers think about our place..Many of the costumers complain the music,others say cos its a boring place and with all the good intention in the world like friend i was thinking cos my information can help him .i didn't t have any interest to take the job of others.i don t wait to promovate me for this was for a good cause.So i make the mistake to tell him what the people think and the result was shocking me.He told me cos i insult him and let me to understand cos our friendship finish..I continue to wandering why he must hate me for this.If i am a boss and any of the workers came to me and tell me cos something s wrong and costumers are not happy i will thank him because he let me know and then i try my best to change thinks in better.I try to explain him cos he got my intention wrong but he don t change his mind.I m not the best waiter i just start work in this domain but i m creative and now bec of the economical crisis i was hoping to can give same help but everything turn against me.Can tell me anyone what opinion have about this? where i mistake? i wold like to know many opinions.any advice?thank u