"You are so bossy and controlling. Stop it!" You can yell as loud and as long as you want to, but that tactic isn't going to work. If someone is bossy and controlling they have a reason, and they aren't going to just stop. It may be a nature thing, or it may be a consequence of nurture. It could be an astrological bent. For all you know, they may have a Leo sun and Capricorn rising. Or, they could have gown up absorbing this tactic. They may have learned that the best way to go about relating to others and to get what you want is to be bossy and attempt to control. If It's their true nature you've got a couple of options: learn to live with it or move along. if you are idly waiting around hoping things will change, you are going to be waiting a very long time. If it's an ingrained pattern, or a learned response to a particular set of circumstances, there is reasonable hope for change.
When people get bossy in response to an issue about the way they are feeling in the world or in a particular situation, it's powerful to identify and explore the trigger.There may be something they are afraid of happening, so they want to keep in complete control to make sure it doesn't. It's also possible they are mad about past events - something you did or didn't do, so now you must... and it's coming out in bossy retribution. Taking the time to understand the motivation for bossy, controlling behavior is the first best step to dealing with it.
The second best step is reclaiming your power. A helpful internal response to dealing with a bossy controlling being brings to my mind one of my dad's old favorite sayings, "So what chicken's butt." Just because someone is being bossy or controlling doesn't mean they have the power to boss or control you. That only happens when you give them permission to do so. You can only be bossed or controlled if you allow it, so don't allow it. Yes, it may be annoying if it's a constant behavior and you happen to be intimately connected (ie. office mate or family member) but that's the extent of it. So instead of bemoaning the other person's frustrating behavior, look at your own bad self and ask: "Why do I care?" What button is it pushing for you? Why is it getting your goat and making your blood boil? Another person can only control you and rob you of your personal power if you let them, they need your acquiescence, your permission. So, Stop. Look and Listen. Get a handle on what's really going on, have a conversation, and let it go.