Late Night Woes at Work

So yeah, I work nights at this diner and let me tell you, it's a real adventure. One night, some guy comes in and he's like super obsessed with ordering the exact same meal every day, chicken salad with ranch dressing on the side. He even brings his own bottle of ranch because he says the one we serve is 'too watery.' Anyway, this one time, I was running late after a friend’s birthday party where everyone wanted to drink until 3 AM and dance like nobody's watching. So I come in, all tired, trying to keep up with my job duties but mostly just pretending everything's fine. This dude comes in asking for his usual, but I had totally forgotten about him from the other nights. He looks at me with these eyes that say 'Why are you so incompetent?' and I try to brush it off by telling him to order whatever he wants today, maybe a change of pace? Well, apparently this was the straw that broke the camel’s back because he starts ranting about how he always gets his chicken salad on time and now look at me. 'Where is my respect?' He spouts like I'm some kind of customer service deity who can control the laws of physics. But here's the kicker: right when things are getting heated, my manager walks over and tells him that all staff have to take breaks, even if customers get upset about it. The guy looks like he’s going to pop a vein in his forehead but then just storms out saying something along the lines of 'I'll be back tomorrow night.' So here's my question: am I really supposed to feel bad for not knowing his little routine? Because let me tell you, running on 3 hours of sleep and trying to make small talk when all I want is to go home and collapse can be a real challenge. Or maybe it’s just part of the job, keep smiling even if your head wants to implode. But then again, maybe there's no point in feeling guilty about something that’s not really my fault? Or am I just being too hard on myself? Anyway, back to work. Another night of trying to make every customer's experience perfect, one chicken salad at a time.