Unaskable question

Do you tell people when something is wrong with them? I.e: bad breath, bat in the cave, smudged mascara, goober in the corner of their eye.... just to mention a few. I usually do. I went on a date a couple weeks ago with a seemingly great guy. He was nice, had his own place, liked animals, seemed stable.... but he had really bad breath. Like really bad. I had just met this guy and I didn't feel like I could say "hey buddy, you have killer breath, want a mint?". And for the rest of the date his bad breath was all I could think about. I couldn't get past it. His friends (yes, I met some of his friends on a first date) didn't say anything to him about it, it didn't improve after he ate and drank. And when he hugged me at the end and went in for a kiss, I think I visibly flinched. A bad breath kiss! Agh!
He wanted to go out again. I said I was very busy but I had had a nice time, yadda yadda yadda. I didn't want to say "you have really bad breath and that's why I don't want to go out with you again!". Maybe I should have. When I have bad breath or smudged makeup or a bat in the cave, as embarrassing as it is in that brief moment when someone tells you, I'd rather know. For the sake of his future dates, I probably should've told him. But I chickened out. Let someone else tell him.
Technically, bad breath is a "fixable problem". It shouldn't have been a make or break thing. Am I really that shallow? Maybe I am. But bad breath or no bad breath, this wasn't the guy for me. Glad I realized that before I spent an entire month's salary on Altoids and Orbitz gum.