He Who laughs last Laughs Best and little doubt about Slangs

I wrote a composition and I'd like someone to correct it,it is about the proverb 'He who laughs last,laughs best',When I was writing it,you may notice that I used some slangs with the word 'suck' for instance,'suck it up,suck up,sucker,etc'.
Here in Brazil,if we write a text with slangs it will problably be wrong and the teacher will tell you to rewrite it.
My doubt is,the slangs I used in the following composition,helped me a lot to express what I meant,they fit very well in the text in my opinion,but is it wrong to use these sort of slangs in these case.
Here is the text:

People ought to be very close to make fun of each other,some people are sucks,they act like a baby going around making fun of everyone,if you've already been reached by one of them,suck it up,don't complain or cry by any means.
The best Thing you can do is to hold on,hold your horses,have some patience,these sort of guys heardly ever aren't found by someone who is as boring as they are.
To prove my point,I have seen recently on the news a group of people making fun of a begger who was asking money to people,only for feeding his two sons,they kicked him,punched him,so,this is a serious problem which takes place mostly In Brazil,where we don't have impunity,enabling people to overcome their ceilings.
If you are a Brazilian or if you live in a country similar to it,don't suck up,don't be afraid of claimingfor your rights because of the power given to our liar government,one thing is for sure,people usually say "The justice always lasts",don't trust them anymore,it is not true,neither is the proverb "He who laughs last,Laughs best,because the ones who have been laughing at the population are the own crooks.

Where do you think I have made a mistake throughout this text,what rating from 0 to 10 would you give this composition,be honest,sincere.

Thanks
Gustavo