Have you ever quit because the mental load was just too much?

It's the Gold Rush mentality. or better said, a Pump-n-dump.

I think there is a mental gymnastics where guests think about the money the spent and feel like taking something worth $10-15 isn't a big deal. 

I think the real estate game is way more beneficial to one's mental and physical wellbeing than playing the stock market where you only sitting inside a house and looking at numbers.So yes, everything you said plus what I said, that's why even I know the stock market can potential yield similar or even better return, I keep real estate my main and stock market as a fun hobby.

And then there is the mental aspect: are you actually satisfied with what you have built.

I've bought, owned, and sold properties that I've never seen and all have made me good money.My mental model is this.  

Not many have that mindset or mentality.

Is there a reason I should start smaller rather than the "go big or go home" mentality?

my ability to regulate emotions, apply strategic pressure, and protect my physical, mental, spiritual, and financial well-being.

Side note he's mentally handicapped and his care taker owns a shop acrossed the street and uses my property to park cars on when lease states that there is no parking on premises.