It's Not Like You

What is the evolutionary benefit of crying? (I just looked it up and everything I saw said that it strengthens emotional bonds between people). So what's the benefit of crying alone when everyone available to comfort you are the causes of your tears?


Anyways.


I hate it when people say "It's not like you" in relation to a behavior. Yes, if people are acting out of sorts, there's probably a problem. Whether or not they know what that problem is is a different story. So there's some merit to saying it, because you have noticed an irregular behavior and are concerned.
What I hate way more is the smaller things, like dressing up a little nicer than you normally do, or wearing a slightly different kind of clothes than you normally do, or not being in the mood for what's normally your favorite food.
That's probably due to my being a teenager. Isn't that what this decade of my life is supposed to be about? Figuring out who I am? And if that's what I'm supposed to be doing, then people shouldn't point out the little things. So I'm trying something new. 
"It's not like you." How do you know what is and isn't like me? I don't even always know what is and isn't like me, so how on Earth can you?
"It's not like you. What's wrong?" You're implying there's something wrong with what I'm doing. You're implying that you want me to stop. You're implying that you don't like the idea that this new thing I'm doing may or may not be me. I'm still talking about the little things.
What about moods? So I'm rather irritable on a given day. "That's not like you." Why am I not allowed to be irritable? Have I broken out of my character outline and you're trying to stuff me back in it? Does it frighten your subconscious that I'm breaking out of the mold you've created for me? So I'm not often this irritable for this long. Keyword: often. It happens sometimes. 
As long as it's not to a dangerous degree or length of time (like depression), there's nothing wrong with me exhibiting an emotion I don't usually exhibit for a little while. 
I am me. This is what you get. What "me" is, well, I'm still sort of figuring that out, but for the moment, as long as (as I said) there's nothing serious or dangerous going on...I suppose you should be prepared for anything. Just because I'm not living in a cocoon doesn't mean these 10-odd years aren't a time of some serious metamorphosing. 
That's the great thing- when "me" is in constant flux, I am everything within that spectrum of flux. I am an electron: you can never simultaneously know both my location and my velocity, but you can figure out my wave equation- you can figure out the area where I might be, and as long as I'm in that cloud, there's probably nothing to worry about.


I'm amused that this turned from a rather emo-teen semi-rant to some quantum mechanics metaphors. Which kind of proves my point.


I think I'll change this blog's subtitle to "a teenager and her literary works...and the other stuff inside her head." Because lately that's been the majority of what I'm posting (although I really should send out some more queries).


QUESTION: Is it okay to sacrifice some minor grammatical conventions (such as using sentence fragments or changing tense for a sentence or two) during an essay in favor of emotional effect?
I'm thinking not so much in this case, since the purpose of my "Ignorance" essay is to prepare for the Sophomore Writing Test in the spring where conventions are a REALLY BIG THING, but what about in general? Most novels have loads of sentence fragments when it comes to narration (and, of course, dialogue). It's how people speak  and think.