Speaking is not enough, though. Simply thinking will make it come true.
Thinking of how poorly the first floor of my Binding of Isaac game was going so far, I immediately was thinking "How excellent a Devil Room with the Mark and the Pact would be!"
So, I got my wish and was reduced to only 4 Soul Hearts. "Ahh, I need more health upgrades for later floors!" I thought. In an item room, I received Mom's Bottle Of Pills and got approximately 4 Health upgrades as well as a bunch of Friends Till the End pills. My run still did not go great... That is until I came across two secret rooms containing Epic Fetus and Ankh.
Coincidentally I was thinking, "This run'll never succeed without Mom's Knife or Epic Fetus and an extra life at that." Alas, I won the run taking no damage from Isaac (I had 1 and 1/2 Soul Hearts). I died on The Chest and Ankh saved me. I only took one Soul Heart of damage from ???
I LOVE YOU BINDING OF ISAAC <3