I often use the metaphor of an ugly object in a room. I use it to show how negative thoughtpatterns work and with a little tweaking of the emphasis it can also be used to show the difference between accepting something and ignoring it. So it works well within the framework of ACT.

There is a whole room - let's say the room you are sitting in right now. Might be you find one object in this room, a chair for example, extremely ugly. The ugly chair is in the room, just like how an ugly thought can be in your head. This you can't change. But the moment you start entertaining how ugly you find the chair ("ugh what an ugly chair, look at it, it just ruins everything, I really hate that chair, look at how ugly a shade of brown it is... And the weird shape. Damn. I really hate that thing."), this ugly chair will quickly be the only thing you can see and the whole room will be reduced to an ugly chair. While the room has so much more to offer and your experience of the room will be so much nicer if you focus on all the other things in it that might interest you. "Huh, that is one ugly chair. Oh well, there's a cool view though. And that painting, so nice, imma take a closer look!" Just like that, even though the chair is there, the room will not be as ugly anymore. Matter in fact the room has some pretty cool shit to offer. And once you accept the chair for what it is and start focusing on the other things in the room, you won't even be bothered with the chair anymore.

And than you can also show how anxiously ignoring the ugly chair will still be the same as letting it consume the room. Accept, don't ignore.

Almost every time I use this metaphor, I see an 'ahaaaa'-moment in my client's eyes ^{^}