Are chessplayers inherently pessimistic?

From a discussion on optimism, pessimism and the process of falsification:

It turns out that most people are apparently not so good at thinking through how their own ideas will fail - checking themselves for weaknesses. This process of auditing one's own ideas for mistakes and hidden consequences is called falsification. Who is good at it, you ask? Well, here's one example: chess masters.... Chess adepts have been shown... to do what they do not just by generating ideas, but by generating them and shooting them down.