Hmm. At restaurants I often assumed they have been slapped before by someone else. But at the beach... Maybe it is that time in autumn when they get cranky.

We often have wasps coming in when we have dinner, they never stung us

Most likely your niece did something to the wasp on accident, or someone near her did. Maybe it was a beach towel, some sand, or a rock hit near the nest.

they swarm around the entrances of the building here this time every year

it's inevitable if you are outdoors enough

That is certainly a point. Maybe I'm not. :)

As someone who has been stung dozens of times by probably at least a half dozen wasps and a few bees... The sting is incredibly variable.

I was doing some yardwork with my daughter and this nest must have been in a shrubby area we were tossing clippings into and one stung my hand and I saw one land on her ear and instantly grabbed her and ran. That was the worst sting I ever had felt and those buggers were small. Now my daughter is terrified of any pollinator.

I spent like 30 minutes icing my sting and she spent like 2 hours screaming with an inflammed ear as I attempted to help her ice it.

I am curious of there are different toxin types and different allergies... Like would those little buggers bring the same pain to everyone.

i have luscious eyelashes. bees, wasps, and similar like to land on my glasses to try to climb onto my lashes. when they're between the glasses and my eyes, uh, it's not fun. but if they crawl far enough in blinking kills them.

I licked... a wasp

That wasp felt harassed I guess. :)
But: Ouch!

Yay.