So I work at an office supplies store that offers printing with quite a lot of services, and I happen to be the specialist for the printing department.
There is an infamous older couple that I have been warned about by my ex-manager, and they come in every now and then to do a lot of printing. The problem is that it's never just as straightforward as "this and this and this please". They bring in lots of books and leaflets and flyers to get photocopied, and then tell you what they want done with each individual piece, only telling you what they want next when you've completed the prior thing. That isn't a huge issue, but with difficult customers it can be a little frustrating. I have heard this couple are frustrating, as well as impatient and demanding, but I've never actually been the one to serve them before - until yesterday.
I see them come into the shop and I internally roll my eyes as I know I'm going to have to be the one who serves them today. I go over all cheery and nice to speak to them, and immediately the woman is being a bit difficult but not overly rude or annoying. The man is being a little demanding, but again not in a totally rude way. The woman leaves after about 10 minutes and it's just me and the gentleman (he is in the shop for about an hour and a half).
Now I went into this interaction thinking I was going to loathe every second of it, but the big plot twist in this tale is that this old dude was the nicest customer I had served all day, and probably for the past few weeks as well! After I handed him every print he was so enthuastic about it, "That's fantastic!" "This is great" "You've done a wonderful job on this" and even though he was definitely overreacting to what was just basic printing, it made me feel so confident and happy! I had to stay an extra hour to serve these guys but it was definitely worth it because I left work in a great mood.
TL;DR: Infamous couple became my new favourite customers. Sometimes it's not the customers who are d*cks, it's your colleagues.