However, generally, people who are trying to control others are doing so because of something they're trying to manage inside themselves. Not to condone, or make it okay, but people who are excessively controlling are doing so because they're managing emotions inside themselves.
This is an approach to the world that is overly rigid, fearful of uncertainty and struggles to feel safe when things are unpredictable. They may also have a very clear idea of what is right and wrong. At the risk of sounding judgmental, they are likely to be - judgmental.
This can be helpful to get clear about, because the natural responses to feeling this control are to react and attack with anger, or withdraw, feel undermined and over time, less competent.
Now that's not to say there is anything wrong with responding with anger, it is a natural response to our boundaries being transgressed, and it can also be a very useful way to reassert our boundaries. But it often isn't effective.
What's more effective is to gently and firmly take a solid view on where that imaginary line is for you. But to do it in a way that doesn't pick up any of the responsibility for how they feel, and making them feel okay. We don't have to take responsibility for their reactions.
This can be hard to explain, but often involves not saying an outright "no" exactly.
"Hey thanks, that's a great suggestion, I'll think it over … I appreciate you taking the time to tell me what your view is … Sounds like you have some knowledge in this area, if I need a hand I'll make sure I ask you first … I really appreciate you telling me how you'd do it … I love how we're different …"
You get the picture.
The aim here is not to change them, if that's ever going to happen, that's up to them. The aim is to shift the dynamic - that invisible, well-rehearsed dance the two of you do. And if, as it sometimes can, this leads to conflict, or even an increased attempt to control, then what comes next is gentle, direct feedback.
Strike when the iron's cold - have the conversation when everyone's calm - and be specific; ideally talk about one incident, how you felt and why you did what you did. "The other day, when you took over that task for me? I felt annoyed and would prefer if you hadn't. I know you know what you're doing, and if I need help, you'll be the first person I ask."
Because, when push comes to shove, we're all control freaks. The problem isn't wanting to be in control, it's knowing what is ours to rightfully control.