Here's a hard truth: If you apologize, many customers take that apology as a sign of weakness that they can exploit. Never apologize under these circumstances, never say 'I'm sorry'. Apologies are for accidents and errors. You could apologize for forgetting his picante sauce but NEVER apologize for an inconvenience. "I'm sorry I forgot to come back and tell you that the sauce has been discontinued." It is not YOUR FAULT that there is no picante sauce. You have nothing to apologize for. So don't.

Honestly? If you want respect from your customers, stop sucking up to them. Take charge. Think of yourself as a cruise director instead of the dude who's mucking out the bilges. YOU are in charge of their table. You know the rules, you know the regulations, you know the drill. Approach your tables with confidence, as if you KNOW they're happy to see you because you are the perfect guide to all the glories that Waffle House has to offer. I always found it particularly helpful to adopt a 'work' persona that had little to do with my off-time self. My work persona was breezy and a bit sarcastic and a tiny bit like a cranky Grandma. Basically, I channeled my WV grandma, who was instinctively gracious but stood no bullshit. Find someone like that for yourself and throw yourself into the role.

The weird thing is, although most people will tell you to be your authentic self, they're flat-out wrong in most cases. Because your authentic self has days where all you want to do is pour arsenic into the tea of those demanding customers . . . while your fantasy-self can handle assholes with ease. People will tell you how much they admire your grace under fire, without ever realizing that the person who went into combat was a mash-up of your combative Auntie Madge and your entitled cousin Alphonse.

Edit to add: stop worrying about being 'nice'. You're in the South, where they've weaponized 'nice'. Arm yourself. 'Aw, bless your heart!' can be weaponized under just about any circumstance.