but you are right. A little bit maybe. Am I mean? Narrow-minded attitude is not appreciated when it comes to the time for formal discussion,I know. Madam Principal is right somehow that I am a tough "Princess" but only once in a blue moon that I am being tough. Mostly I can pretend that I am very cute. ... However, matter-of-factly, yesterday it actually was one of my thoses days, I was sort of moody due to something. Too bad so sad I got you. I shot you with so many stinky eggs which deliverd by bro 2---he produces eggs in his farm.
You are right that slang could be very confusing, even sometimes I think it is a slang term but they said it is their make-up word, for example, "speedy go fast " means sneekers--ruuning shoes. so, indeed, a speech with full of slang expressions could be a nuisance.
I mostly agree with you that using slang when writing is not professional, but one thing I want to point out is that in the some informal occasions, using slang terms doesn't mean the speakers are not educated, it really depends on individuals. Some people are high-educated but when hanging out their friends and family they use slang a lot, and in the workplace or other formal occasions they are able to fit themselves in well and can deliver graceful speech in suitably dignified language.