Can confirm. Mules and donkeys are mean, territorial things. And those bites hurt. Pissed one off as a kid. Never again xD

Working on commissions means you get a percentage of whatever you sell though... Your pay is literally based off of what or how much you sell as well, hence the no hourly wage. It's not really the same. Because even if you provide mediocre service and still sell something, you get paid based off what it is. Sell cars? Thats still a nice check. Furniture? That's pricey too. Real estate? Same thing.
But you can give fantastic service to someone who takes up your table for 4 hours, runs you ragged, and they leave you a $5 tip on a $150 check. You make maybe $5/hr, if you're lucky. So you've now busted your ass for 4 hours, and made $25- before taxes. You don't have to like tipping as a custom, but realize that by holding onto that arrogant attitude you're not helping anyone except yourself. You only hurt whoever is unlucky enough to have to serve you.