Doing the right thing...is doing what exactly???

My whole life I try to do the right thing...or what I think would be the right thing to do...
When I first came to high school a lot of people didn't like me cuz they thought I was too matured. WTH?? TOO MATURED?? There is no way that I'm TOO matured!!
What's wrong with doing the right thing?? Well, in some cases, you'll always hurt someone you care about, even if you have no intention to do so...

I have a situation right now, and I have absolutely no idea what The Right Thing To Do is...
Well, I've got a friend, u see...She's one of my besties, and she's a wonderful person, really, but...maybe her other side isn't that wonderful...swearing, wild imagination, grudges on ppl...well there's more but since I'm not a cruel person, I will not say no more bout her cuz she's my besties...her other side doesn't really matter much to me actually...but something made me realize otherwise...
We always hang out with our other friends and we always make jokes and stuff...and sometimes we insult things we hate...talk about nonsense sometime...She always asks me advice on relationships and her big future and sutff...So that got me thinking, What if I'm ENCOURAGING her to be worse?? But I need to be honest with her now...It's not fair to pretend anymore, even though I never realized that I was pretending in the first place...I NEED to tell her what she's doing wrong, what she should do, what she should stop doing...But, she's quite a complicated person...and I just know that it's not going to end very well...
If I'm gonna tell her that, she will reply something like this, "Nobody can ask me to change except my family!!" What am I going to do with that answer, huh??
She's going to hate me for life!! But as a friend, a true friend *stick out tongue*, I think that I should do the right thing to make her a better person...she's still quite young, there's lots of room for improvement...
But what if she totally ignores me? Then she might become worse...I'm actually scared of that...
To make sure she knows what she's doing wrong, to let her know what the consequences would be, and of course, to help her reach her potential to be the best that she can be in the best way...
God brought us together for a reason...
I pray to God that He will guide me along the way...InsyaAllah
So I guess I don't care if ppl think I'm too matured, too weird, too whatever, as long as I do the right thing that God wants me to do, it shouldn't matter...
May God guide us all to the right path...