Slack's Stewart Butterfield knows: There’s more to a pivot than a sharp left turn. First, there’s the opportunity you’re pivoting toward. Can you see it clearly enough to navigate toward it? Can you convince others to come along? Then you have to pivot away from your old idea. This can be incredibly difficult, because it involves humans. And humans don't tend to let go of old ideas easily. You risk blowback from your co-founders, your staff, your investors and your users. This will likely be be the single greatest test of your leadership skills, because your credibility will come under scrutiny. The moment you find the thing that your users cannot stop doing, you need to slash and burn the rest of your business.