Never say.../Always say...

Suspicious things people say. Things that tell you there is something wrong, despite what the words seem to mean.

"It's harmless".
If it's really harmless, no-one would need to say that, would they? Do you hear, "Well, breathing oxygen's harmless enough"? So they really mean, "Whatever it is I am doing, I know there's something wrong with it but I'm not quite sure what, and besides I want to do it".

"I know what I'm doing".
Number one sign that someone DOESN'T know what they are doing. Otherwise, would they need to say it? Means, "It may look like everything is wrong with what I am doing, you may feel sure the outcome will be bad, but..." (but...you are right!)

"I am not mad".
I don't even need to comment on this one. I heard it a few times, and somehow never quite believed the speaker!

As for people who say "Never say...", they're not saying something positive. If you say to someone, "Don't kill me" (to take one of the less common examples) then, yes, the word 'don't' is there, but so is "kill me". Would it be better to think of something positive to say to them? "Send me flowers" - there's no killing in that one.

I am thinking a positive statement is a good one.

So, yes, maybe, "never say never".

But definitely always say always.