This tale is from my first day on the job when I was 16 and 1 day. Green as grass.
My first customer ever comes up to me.
Customer: "Do you know where the garbage bags are?"
Me: "No, sorry it's my first day."
Customer: "But you do know what garbage bags are right?"
Me: "... yes"
Customer: "Then why don't you know where they are?"
$me: "um... I'll help you look"
The store had 100 aisles so it was pretty big. I make an educated guess and lead him to the proper aisle on the first try
Me: picks up a box of regular black garbage bags, "Here you go, Sir"
Customer: "No, I need gaaaaaarbage baaaaags", he picks up a box of compost garbage bags right next to it, "I can't believe you have never seen these before", starts laughing
Me: blank stare, "I have"
Customer: now dying of laughter, "Boy, you really are useless you know that!"
Me: "haha, yeah", what the hell is happening
Customer: "Now you know!", walks away
Me: I guess this is my life now
Sidenote: in Toronto, you have to separate your garbage into compost (food, tissues, paper towels) and regular garbage. You must throw away compost in compost garbage bags.