TIFU by handing my boss a t-shirt

Not today, but many years ago, I worked for a popular teddy bear building toy store. Most of the staff was in their late teens, like I was, but our boss was a woman in her 40s. Our uniforms were iconically hideous: denim dress shirts with itchy embroidery on the top left chest, khaki pants, a brown or navy belt, white shoes and white socks (and yes, you'd get sent home if your socks weren't white enough!).

I hated wearing this uniform, but thankfully once a month we would have a special "Sale Weekend" during which corporate headquarters would send us seasonally themed t-shirts that we would be able to wear instead of our Canadian Tuxedo tops. Respite, if only for a few short days.

One year, in December, we were having our annual Christmas sale, so corporate sent us a box of bright red and green t-shirts. I was so excited by these 100% cotton gifts-from-god that I volunteered to hand them out to the rest of the staff, like one of Santa's diligent yet underpaid elves.

The shirts were stacked in the box by size, with the smallest on the top. Knowing that my boss was the oldest and largest among us, I grabbed the shirt at the very bottom and gleefully went into her office to give it to her. She took one look at the tag (which I should have done in the first place), handed it back to me and said "This one isn't my size". Confused, both by my mistake and her icy cold stare, I returned to the store room to try and figure out what went wrong.

I grabbed the box of remaining t-shirts and started counting them out - there was exactly one shirt for every staff member, no more and no less. But then, whose shirt was in my hand? Whose shirt did I try to give my boss that caused her to contemplate my murder?

Finally, I checked the tag, which instead of a size, simply read "Bearemy".

The shirt was for our mascot. Our giant, stuffed, teddy bear mascot. It was meant to go overtop of the already huge costume, so it was extra SUPER big.

No wonder my boss wanted to murder me.

TL:DR I didn't look at the tag on a t-shirt and accidentally insinuated that my boss was fatter than a corporate mascot