Starting your sentences with "Let..." outside of a math textbook

Underrated post desu

Let me introduce myself

Lethargy is a blight among our young male population.

Let us assume that Frank can get friday off, then it'll be ez to get a ride bruh

(real text I sent today)

Let OP be a faggot [the "Universal" axiom]

It's going too far for me. I'm now starting a lot of sentences with:
>note
>in particular
>let
>suppose
>assume
>if ... then

This /autism/ general?

Am I the only who finds this language slightly obnoxious, even in math textbooks?

As long aa you don't start with
>it is obvious tha
>it can be shown

No, I also hate it.
I'm in the middle of a class with "Mechanics of Materials" by F. Beer and it's possibly the worst written textbook I've ever read - even though the information is good the shitty writing makes it hard to follow. There's a phrase seriously like 2 or 3 times a sentence.