The best way to learn proper English is to read news report, and watch news on TV. Watching TV shows is a great way to learn casual English, slang words, understand culture reference and humor. If you have already watched these shows then you may recall the words used in the following dialogs.

Look, I'm sorry
you're UPSET with me,
The Big Bang Theory Season 7, Episode 10

- It's absurd.
- I didn't think you'd be so UPSET about it.
Game of Thrones Season 1, Episode 4

Please, don't be UPSET. I just...
The Big Bang Theory Season 6, Episode 6

He's UPSET with me.
I should be the one who talks to him.
The Big Bang Theory Season 10, Episode 12

People were so UPSET about it,
The Big Bang Theory Season 10, Episode 21