From these my fav is “Learn to say No without explaining yourself”.
http://www.becomingminimalist.com/simple-living-images/
My first unexplained No was loud and clear. I was in a meeting room with our former business partners and their lawyers. The wanted a deal and made an offer. I could hear their expensive watches ticking. I said No. To their disbelief. To my astonishment. And a silent joy. Threats followed. My No stoods its ground. It made them say Yes to our offer. We cleaned the accounts and closed the noisy chapter. The rest is history. It was cool. And worth it.
You may want to Try it next time. Try it. And enjoy it all!
Thank you, becomingminimalist.com for inspiration.