Two completely fictional characters, not based on reality at all

Two people, let's call them M and K, are enjoying a cold but gentle saunter around The Hague. Suddenly, M takes a slightly bigger step with his left foot while his right knee seems to buckle somewhat... but then he's back in stride as if nothing has happened. K notes this, finds it rather peculiar but she generally finds him rather peculiar so mentions nothing of it.

A few metres later, M does it again - the same abrupt, slightly longer stride that looks like an aborted half-lunge. And then, back into step as if nothing has happened. Again, K says nothing because she is starting to look forward to this move. On the third such step-lunge, K collapses into incapacitating giggles (usually reserved for precarious balancing chores, such as when they are trying to rotate the sleeper couch and M is bearing most of the weight).

Bemused, M queries this sudden outburst of laughter. K asks what the new goose-step is all about. M explains that the bottom of his jean-pant keeps getting caught underneath his right heel, so instead of doing the foot-out-shake-it-all-about dance, he opted for the jolt-lunge-step. "I thought it was more subtle," he concludes.

"It's not," K assures him, demonstrating her delight with sporadic limp-step-lunges the rest of the way home.

Another little M+K walkabout incident -

M and K go to the shops on a busy Saturday afternoon. After an hour and a bit, while standing in one of the swankiest stores on the swankiest shopping street (M and K don't usually shop there, but sometimes they like to pretend they belong), M happens to look down and finally notices why things were a bit breezier than they should be.

M: Aaaaah crap... my fly is down.
K: Oh ja, I noticed when we were leaving the flat.
M: WHAT? Were you planning on telling me, like, ever?
K: Sure... but then I got distracted and forgot.
M throws his head back in exasperation (while surreptitiously trying to redress himself)
K: Whaaaat... how many people have actually studied your crotch in the last ninety minutes? No one cares.
M: Except me.
K shrugs: Except you.

Some may ask why M puts up with K.
M asks himself this regularly.