Sentence 1: I was working in a mall as a sales staff. 
 Sentence 3: He always demands what he wanted like he is our boss 
 Sentence 4:  Until he shouted at me because he is complaining 
 Sentence 5:  But all i can do is to keep calm and stay humble 
 Option 1: Then there's this one customer who is so arrogant. 
 Option 2: I hadn't had a customer all day.