It's Monday can have many connotations which vary from positive to negative. The most common is when having a weird day just to throw out an "Its Monday" to validate the weirdness or shitness of the situation. Unfortunately "It's Monday" cannot actually be used on a Monday as thats just wrong .

The most painful day of the week.

A day generally created for the purpose of making people wish they were someone else. The day you realize you have 4 days of work ahead of you and that they won't be going by fast at all. Symptoms generally include feeling like crap, wishing you were dead, or not showing up for work in general.

The day kids dread going back to the hell hole called school

-An excruciatingly long unit of time
-Another way to say never.

This originated by a Playboi Carti tweet, only saying: “.MoNDaY”. To most fans expectations, nothing has happened on Monday.

The biggest waste, of exactly one seventh of your life.

The worst fucking day of the week. It should go crawl in a corner and kill itself.