I have a piece of advice for you. It comes from my wealth of experience and observation, and is absolutely free. On second thought, maybe I should charge you, so that you feel my advice is valuable.
Heck....I don't want to be bothered making change....so free it is.
This is what I have learned, and you would be wise to take it to heart so you can avoid having to learn it the hard way: Do not assume that you can change another person.
It astounds me how many times I have heard someone tell a story about a friend with a flaw, and how they felt obligated to tell that friend how to improve themself. In not one of these stories has the friend asked for assistance with their flaw. In most cases, they don't even perceive they are flawed, and might have merrily gone their way enjoying life until their "friend" set them straight.
The point that is most often missed, is that it is improper for you to tell your friend he needs to change. It's from YOUR perspective that he could improve his life. He may be totally satisfied with who or what he is. Unless he solicits your assistance with a perceived problem, you need to mind your own business.
As a general rule, we do not succeed in changing ourselves unless WE make the decision to change. It is necessary for change to come from within to be successful. Modification based on someone else's efforts is never permanent. You've all heard it......until YOU are ready to change, your efforts will be wasted.
It's probable you will hurt your friend by suggesting that they are not perfect in your eyes. Even though you are trying to do a kindness, you will simply bring your friend hurt.
So, the advice lady is here to say: "Mind your own business!" See to your own faults, and simply enjoy your friends. If something about them drives you crazy, it is YOUR problem, not theirs! You have the choice; you can accept them as they are, or you can walk away.
(getting down off the soapbox....) If you don't take my advice, that's okay. :-)
It's not my job to change you!