Moments like these in life, especially after lots of time and effort, tend to be incredibly frustrating. Frustration leads to anger. I'm actually surprised at how well I've held it together (anger-wise) during this harrowing time of my life. Years ago, mostly as a teenager, I was a rage machine. The smallest thing could set me off and I'd be grumpy and moody for an unreasonable amount of time. As I've aged I like to think I've matured a lot and have gotten a better handle at my emotions and my reactions. But still, there are times when it's just too much. I'm sure you've been there. I'm sure we've all been there. It's only natural; we're humans. And other humans sure can piss you off.
As we grow older and get more life experience, we start to realize that not everything can be fixed. You can't control how other people act or what they say. You can try talking to them (rationally and calmly) but that doesn't always guarantee a change will happen. You can try to change yourself, but you also have to ask yourself if it's really you who is the one who needs to change or just how much you can possibly change to better the situation. The one thing I have learned, though, and one of the only things that really ever works for your own benefit, is the way you react to these events and people who make you feel this way. All you really have control of is yourself. Your words, your actions, your reactions, your expressions, your attitude, etc. It's not always easy, but it's something worth working on because it will help you out throughout life many, many times.
So when something, or someone, frustrates you to the point where you want to go ahead and smash all the plates, take a moment to breathe and just think. Give yourself even just ten seconds to calm down. You have the power to control it. You can walk away. You can figure out a way to make changes, probably at a later time. Or you can even just do something else to take your mind completely off whatever it is that is making you feel that way.
Also, keep in mind: Nobody is perfect. Everyone makes mistakes. It's how we handle those mistakes that truly define us.