Larry from U2 says: The songs had a lot of things going for them, but they had no magic, that thing that separates the ordinary from the extraordinary. It's hard to put your finger on but the songs just weren't ready. It was a very difficult thing to say to Bono and Edge. Bono was really pushing for us to release those songs. He was unhappy when we didn't agree with him. This is not a conversation you have with your mates, who are working very hard, unless you feel sure you're right.
--- I have problems with understanding the last sentence. Maybe paraphrasing would help?
To me it means something like that: However when you're sure that you're right, the only thing you can do is to say what you think and persist.
Top answer
It just means "This is not something you say to your mates ... unless you feel sure you're right".
— Mr Wordy
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