modus operandi

Some people have those thought about choir? That's surprised me.

People I met don't dismiss choir but have strange stereotype about those in choir. "You join choir, you want to be the singing star." or "You're member of choir, you're grades must be good!" Where these conclusions come from? (shake head)

As for 「思い出はいつもきれいな」, I guess it should be 思い出はいつもきれいだ(普通体) or 思い出はいつもきれいです(丁寧体)?
I think na-adjective has na when it with a noun, like きれいな花, if put it at the end of sentence, it won't have na.
Or maybe you want to say だな? Japanese is such a confused language LOL