Are tubes really “warm”?


Time and again I read posts that claim/assume that tubes sound “warm.” I have not found this to be the case. Having owned many high quality tube amps and preamps, I find that tube electronics present more natural highs than many ss designs. But warm?? Not in my experience. Can someone explain what it is about the tube sound that many consider “warm?”
cakids
Tubes to SS are sort of like analog to digital. Many think this has to do with even order harmonic distortion. I do not say warm. I would say ambient is more like it. Tubes and analog seem to be more ambient. This is euphoric and not necessarily accurate, a very old argument. Like Nelson Pass says, "audiophiles just want to be happy." I say audiophiles just want to torture themselves. 
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This is always fun.  A coworker stops buy, walks in the front door sees tube stuff. We listen to a few songs, he says he enjoyed the listen, and never realised tubes could sound so, so wonderful.. I never said a word... It's ALL SS.  Another time, visa versa. I get told how SS is so much better, clean, sharp, dynamic, bass is right there... We're listening to all Valves.. Might be 50-60 year old tec too.. I never say a word..
Same guy, would NEVER go for a class d.. or tubes.. C20, Nord NC500
He knew it was my Krell/Krell set up...Just knew it...
LOL...Hay when it's right it's right.. Who cares... I'm stuck on better, for a reasonable $$$$$ amount.

Regards