Competing with each other would be trying to one-up each other feature-wise, whereas what I have witnessed was things like discussing trade-offs made in different languages and juggling around ideas on if some feature from language A would make sense in language B too.
"Head over heels" is actually a corruption of "heels over head".
It's one of those corruptions which flips the meaning (ironically, in this case!) on its head, or just becomes meaningless over time as it's reinterpreted (like "the exception that proves the rule" or "begs the question").
What is the difference? Using polite words to communicate?