Just did it Friday.
Have a 2022 GMC Diesel....left work, pissed as hell at my boss, went to the pumps and pumped about 5 gallons of unleaded in it. Now, I've never had a diesel before and my mind was murderous at the time (even moreso after my blunder). Got my truck back today and am 650 lighter in the wallet.
Ugh.
I'm an idiot. But that won't happen again.