That cereal tastes so good.!

for emphasis

How could he treat you like a doormat while treating his pet like a princess?

i understnad u but why did u put pet?

It's so discriminatoryThis is so unfair.

discriminatory = based on race, religion, skin color, gender, age etc

Language learning takes years to master,earning a language to fluency will take a few years so don't get ahead of yourself ¶
4.

- I docan't believe she actually did it.

I don't = dismissive

- Well, she did it all right, but I assure you there won't be a second time.certainly did it, but what she did was coincidental.

Hey, Susan, it's been a long time since I've seen you.

= 好久不见

Let's do some catching-up./ Let's catch up a little bit.catch up some time.

I mean, I can never tell.'t tell the difference.

My phone's charger is broken.

的

I couldn't charge in.So, I wasn't able to charge my phone.

Do you feel the way that helike he's desperate? He's trying so hard to lobotomize himself to blend in?blend in and be considered "normal".

people pleasing or arrogance? which one? idk what ur trying to say.

if its arrogance it would be

Do you feel like he's arrogant? He's trying so hard to blend in and be considered "normal".

Oh, so patronizing.

Thatis cereal tastes so good.

"This" feels more natural because the sentence seems like you are eating the cereal right now.

It's so discriminatory.

This is not wrong per se but feels a little strange.
Other options:
It's so inconsiderate.
It's so typical (of men).

Language learning takes years to master, so don't get ahead of yourself ¶
4.

This feels a little negative. "Don't get ahead of yourself" has a meaning like not putting yourself in a position you don't have a right to be in.
A more encouraging way to say it could be "so take it one step at a time" or "so be patient with your progress".

- I don't believe she actually did it.

Or, I can't believe she actually did it. I'm not sure which is better without more context.

How do you differentiate a prairie dog from a groundhog?

This is fine, but a more natural, colloquial way to say it is "How do you tell the difference between a prairie dog and a groundhog?"

I mean, I can never tell.

"Differentiate" is a more formal word and doesn't match the tone if you say, "I mean", which is casual.

I couldn't charge inmy phone.

Or did you mean, "I couldn't plug it in"?

Doid you feelnotice the way that he had to lobotomize himselfdumb it down (or act stupid) to blend in?

Oh, so patronizinghetic.

I'm not really sure what was intended with these last two sentences, so I made up some context of a generally smart person who is acting stupid to fit in.