The silent stare is so effective. I learned about it in social psychology in undergrad, and have often used it to great effect. Probably the best example is when I went to sign the papers on the car I was buying—I had already worked out a price and my trade-in with the salesmen the day before—and they decided they were going to take $1000 off the value of my trade-in. (I want to emphasize that I was buying a 10+ year old car; I ended up paying $8k total.)
"No," I said. "That doesn't work for me. If you're unwilling to honor the deal we made, I'm not buying a car from you."
Well, they talk for a living. So they talked. Here I am, a young woman on my own, and these two men at the dealership are giving me all the reasons they couldn't possibly honor the deal we made yesterday.
So I sat. I didn't say a word. I just stared at them.
They kept talking, trying to get a reaction out of me. After about 10 seconds, they abandoned all pretense of logical arguments and started hammering pathos. They weren't even buying my old car from me for the dealership; it was a personal favor for which they were using their own hard-earned money to help this poor guy at church who just got out of rehab and his house burned down and his children exploded and his dog left him for another man, etc etc
I didn't say a word. I just stared at them.
They began falling apart. They continued trying to hustle me, but their confidence left them. I think they might have been sweating.
Within five minutes they caved and signed the papers for our original deal.