|The eternal tug of war between whether to go forward or whether to pull back (source)|
The other side says, "Hey, we've gone too far. Let's stop this thing, NOW!"
The first is the voice of the Yaysayer "YAY! Let's do this thing!"
The second is the voice of the Naysayer "NAY! Let's not do this thing!"
Stop or go, move forward or pull back, seize or cease, the tension between these two forces characterizes much of the action behind what makes an open world fun. At the same time, the Yaysayer and the Naysayer are often seen as adversaries, one impulse comes at the cost of another. When the action runs high, tempers can flare, people can get stuck in their ways, and well we all know what comes after that.
But it doesn't have to be like that. The Yaysayer and the Naysayer don't really have to be at odds with each other. Both usually want the same thing- fulfilment and success- they just go about it from different perspectives. The former is about acquiring and achieving new things; whereas the latter is about preserving what what's been already gained and reflecting upon it. On average, you need one to do the other- to achieve new things you need prior resources, and to have prior resources to conserve you need to take risks to get them in the first place.
I've found that the group can work really well when there is a dialogue between the Yaysayer and the Naysayer and they use their perspectives to augment and complement each other. The Yaysayer can pull the Naysayer out of his comfort zone while at the same time allowing the Naysayer practice to refine his critical skills on evaluating plans of action. On the other hand, the Naysayer can refine the Yaysayer's daring plot with further developments to make the plan more successful.
Even in disagreement, there can be gains for both parties provided they reciprocate good will to each other. When the Yaysayer wins out, sometimes the Naysayer will be pleasantly surprised with the luck of the draw and an unexpected reward, not to mention later experience to draw from in evaluating dangers. When the Naysayer wins out, the Yaysayer can explore further chances for alternative ideas with the Naysayer.
So we might think of it this way. The Naysayer can allow the Yaysayer to be even more daring knowing the Naysayer has her back, and the Yaysayer allows the Naysayer to be even more evaluative and reflective by providing the Naysayer with things to critique.