Cashiers / Laundry

It drives me absolutely bonkers when I ask for change in looneys and the cashier looks at me like I'm insane. Today, I had to get change for laundry. Our machine, like many machines in buildings, only takes looneys and quarters. I figured, "where better to get looneys in change than DOLLARAMA?"

But no! In fact, I went to the dollarama, and bought a couple things just so that the cashier doesn't have to give me $19 in change (I had taken out a $20 for this whole endeavor). So I hand her the bill and ask for AS MANY LOONEYS as possible. Not even ALL LOONEYS, and she looks at me like I just asked for her first born child. She says, "ugh! all this???!?!" and I replied, "Yes, I'm sorry, it's for my laundry machine." She works at a DOLLAR STORE! Her cash register is FULL of fucking looneys! THAT's why I went there, and she looks SO put out. I will enumerate the reasons this pissed me off:

1) It's for the laundry machine, and I specifically told her that. That's why I was getting change. It's not like I just like to have the change pocket in my wallet full of heavy coins.
2) It's the DOLLAR store. DOLLARS. That's what I want! That's why I went there. To get DOLLARS! THAT's why I didn't go to the depanneur or some other store that doesn't deal primarily with dollars.
3) She's a cashier! What's the big fucking deal??! Don't give me a $10 bill, just give me 10 X $1.00. It'll take you all of an extra 2 seconds, and it's your JOB you idiot. You give change for a living.
4) Okay, so maybe it's slightly annoying, but it's totally rude to make me feel bad for asking for specific change. I left the dollar store apologizing and feeling shamed that I had to get change like that. What gives her the right to make me feel that way?