Colleague: The user said this [Total line] is not the average she expected.
Me: Okay? But she knows that averages are weighted?
Colleague: I'm gonna call her.

... 30 minutes fast forward

Colleague: Okay she wants an average, but she wants us to divide it by something else.
Me: Okay? But she knows an average is the sum of one thing divided by the sum of another thing and not just anything?
Colleague: Yeah, she said she wants it to be kinda this in relation to that.
Me: Okay, so rather some percentage value?
Colleague: To be honest, she just wanted to reproduce this old Excel formula.

God has left this planet ... and I admire my colleague for not completely freaking out in the face of the user.