Oh no, here I go ... call 911 if I'm not out of this in a week

DaveS - but it's nonsense to try and use 'competing with yourself' as a synonym for 'self-improvement', or indeed to describe anything that actually exists.
I strongly disagree and say that through usage this has incredible meaning and in fact motivates hundred of millions of people to become better - and they do think of it as "competing against themself".
Yes, there are all kinds of words and phrases that don't make any literal sense, however they are commonly used.
You might as well say "What's Up?" doesn't make any sense. It's a phrase that gets used probably billions of times a day and everyone knows what it means, but nobody (ok, probably 10,000 people a day who THINK they're funny) actually looks upward and describes what they see.
So, my point being, that if millions of people use this idea of "competing against themself" to improve, what's the harm or problem? Because you don't like the way the literal definition of the words mixes?
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Now for competition - it's been covered that parkour won't be "completely" competitive, I'm personally going to make sure of that because I will practice by myself until they put me in the ground, I'll practice in my own back yard, in an alley, in the woods, wherever I can / want to / am able to. So in the sense of "competing against others for a prize or purpose" parkour will be safe by at least one person at least as long as I am able to train.
Each person is welcome to do the same.
Competition is everywhere, it is part of the nature of existence. (challenge - debate that as fact)
I don't feel that anyone can deny that at least 50% of the population of the world sees competition as something that inherently exists in life. Scientificially, if you believe that things evolve, then competition is part of life.
Can you name a game for me that is not competitive? I can name a few
Catch.
Fetch.
The majority of games are based in competition, whether it's played by kids, animals, adults, professionals, recreationalists.
I think we can even say that the majority of non-passive recreation exists in competitive environments. How many people play video games worldwide? How many of those have no competitive element? How many people play sports worldwide? How many of those are non-competitive?
How about this:
Walk into a toy store, a big one, a really big one!
starting at the very beginning, examine every item in the store and see which ones have a competitive element or for which a competition exists. I am willing to bet that you end up at over 80%. you can start with the
gumballs they sell in the machine on your way in, move to action figures of army soldiers, barbies with corvettes and bigger and bigger houses and smaller and smaller waists ... the
etch-a-sketch.
God forbid we go to the Guiness book of world records - after all, what is a record? It is a comparison of an achievements to the similar achievements of others (competition). Over 100 million copies sold by 2004 and 11,000,000 visitors a year to their website. I have to say that this points out that MANY people like competition. It is the world's most sold copyrighted book.
Business is inherently competitive - how many people work for a business that competes in some way. Even Charities compete for people's attention and resources.
Anyone or everyone is welcome to not like competition, not agree with the premises, whatever you want, but you can't deny that many humans enjoy competition and that competition is in fact everywhere.
Now, how it affects you - that's up to you ....