Many leaders of midsize companies –  especially if they’re the founders – are constitutionally inclined to see new opportunities around every corner. And they love to pursue them, deadline commitments or old strategies be damned. They forget that the strategy which took them from small to midsize has already proven itself a winner. But a new vision is always more exciting to them than the present one. So they begin tinkering with their core strategy, burning up resources while their companies wander off their tried-and-true growth path.