Michelle needed to shower, but had dirty hands which she, being only three and a half years old, wanted to first wash in the basin. The shower was already running and I had wanted her to get in and wash her hands there. (Silly little things one fights about , hey?)
Instead of doing what I usually do, which is to pick her up, kicking and screaming and plonking her in the shower, (and having a distraught child for hours afterwards), I said " Michelle, I'm cross that I am not being listened to. At the same time washing hands in the basin would waste precious water. So, I'm turning off the shower and going away for five minutes so I can cool down. I'll come and help you shower when I'm feeling calmer.'
Which I did, without confrontation or resentment. Just do something different - very powerful!