The meaning of speech is inseparably entangled within the context of both the speaker and the listener, with the most commonly significant piece of that being "Why did you say anything at all?". In the case of "You missed a spot", the speaker is exerting their desire for a spot to get cleaned onto the person already doing the cleaning. Best case scenario, the cleaner is already cleaning for the speaker, in which case the implied command to clean the particular spot is merely a redundant part of a broader command to clean in the first place. In the more commonly aggravating scenario, the speaker is not the intended beneficiary of the cleaning, and the act of commenting on it at all is met with the hostility appropriate of some one trying to control you.

In the example of the avocado toast guy, why did he say anything at all? The subtext of "all you have to do to save money is stop spending money on frivolous things" is that it is a defense of the status quo: "You shouldn't complain about our unfair economic system, your suffering is your own fault". But why make that statement? Because the speaker is broadcasting to the world that he thinks he's better than the avocado eating proles.

The choice to say anything at all is an even bigger choice than what to say.