jackhammers.

Concrete is good stuff. It's durable, it's strong, it takes a lot of energy to break apart. 

Which is great until you want to break it apart. You'll need a jackhammer. 

Jackhammers are loud, noisy, and, I imagine, if you're the concrete, very painful. 

Beliefs, traditions, and history can be a lot like concrete. Solid. Durable. Hold up to lots of wear and tear. But, if you want to, or need to, change them, well... get ready for some noise and some mess. It's not going to feel comfortable when it's done to you or when you're doing it to someone else. 

At the same time, concrete starts off more soft. Malleable. Formable. To keep it that way you move it, stir it up, to mix it up, you don't let it sit still. 

You can figure out which things you want to form and which you don't. I, for one, am trying to keep more things malleable, stirred up, constantly moving, before I let them sit. That stuff that needs a jackhammer isn't fun.