I think the one showing that human beings broadcast chemical signals reflecting their emotional state could be potentially quite important. And who would have thought that a simple hydrocarbon like isoprene would be involved:
But this is the molecule from which rubber is made. It seems that it does appear in biology quite a bit.
Some of us remember "Does your chewing gum lose it's flavor on the bedpost overnight?" Now we know it's due to bacteria.
And now that so much work has gone into the feline communication vocabulary, we can look forward to google translate doing cat to human and human to cat.