It's tempting to try. And I have multiple times, but I never managed to make anything stick.
I've ran workshops to get people thinking differently and pushed to add accessibility to the definition of done at the same time. I thought I'd cover both bases. What's the harm in that?!
The harm is that they pull in opposite directions.
Changing thinking asks people to explore, question and reflect. It needs space and patience. I was saying they can take their time and figure out what it means for how they work.
Changing behaviour says the opposite. I was forcing them to follow a script, every time without any exceptions. There was no room for them to figure out how they felt about it.
The problem is that when you run both at once, you muddy that message. People can spot the ambiguity. And ambiguity is a brilliant excuse not to change anything. If it's not clear what's actually expected, most people will default to what they already do.
You can't forget the question of bandwidth. People can only absorb so much change at once. Asking them to shift their thinking and their behaviour at the same time is a lot. One has to give and it's usually the behaviour that suffers, because thinking feels like progress even when nothing has actually changed yet.
Trying to bring both at once means you're probably not doing either well enough.
Pick one. Do it properly. Let the other one follow.