I once told a close friend that I had many very difficult tasks to accomplish over a short period of time. I was preparing for my comprehensives, organizing a conference, writing talks for two conferences and doing revisions on an article.
"You can do it!" my kind friend said. "I believe in you. You can achieve anything you want because you are strong and determined."
"Oh no," I said. "No, no, no. You are doing this all wrong. This isn't what I need you to say."
"What should I say?" the friend asked.
"You should tell me that there is no way I could do this. That it's completely impossible and that it will never happen."
"I don't want to say that, though," my friend responded. "For one, I don't think it's true. And it also sounds kind of mean."
"But that's what I need," I said. "This is what works for me."
"OK," the friend responded tentatively. "You will not be able to do this? It's impossible? It will never happen?"
"Ha!" I exclaimed. "I'll show you that it is definitely possible! I can do it! Thank you!"
Then I rushed home feeling extremely motivated and productive.