Rude & entitled owners

A while ago myself & my friend went to Apollo for milkshakes & a catch up, whilst we were there, a gentleman at a table near us had a complaint regarding the quality of his food, I must say the customer was actually quite pleasant & simply explained why he was not entirely happy & asked them to correct it, he was calm & spoke very nicely to the waitress, but then the owner came to his table screaming & yelling at him. Both myself & my friends felt extremely uncomfortable, we were absolutely shocked, we quickly paid our bill & left, we didn't know how far this was going to escalate. The customer sat there looking extremely confused & in shock, we felt terrible for him! I must say, I have lived in the area for many years & we have been going there for their milkshakes for quite some time because I will be honest, they are delicious, but that was not the first time I have witnessed the owner being rude & actually quite aggressive with a client. Even if you served the best food (which they don't) that still doesn't give you the right to treat another human being like that, let alone a client! As I mentioned this was a while ago, but after hearing other people in the area talk about the ********** service from the owner at Apollo as well as reading other reviews online, I felt it important to share my experience. I hope the owner reads all of the reviews online and realizes he may have an anger problem, I hope he seeks help if this is the case so that his business will thrive!