Boundaries Question

Hi dear coaches, I came to this question; what is the hardest boundaries for you to enforce. I found that for example I want to do the specific things in an specific way at work.If someone wants to help me because maybe she has to do it since this is work but she didn’t do the exact way that I said n started to argue with me that it is fine there is nothing wrong. I have a hard time to tell her if you not listen to me, I will not let you to participate. It happens to me a lot even in family situation at the end I prefer to do on my own. My question is how I can get the other people cooperation but without force or without resentment and ask them to do exactly the way what I want?