Board Thread:The Gatehouse/@comment-66.60.76.2-20140123140944/@comment-24234477-20140123171029

Red to-dos will not do you any damage; they're just worth more when you complete them. (The assumption is a to-do been on the list for a while, you are procrastinating a task you don't want to do, and thus you should get greater rewards for making yourself do it.)

You can add a due date by editing the task and using the Due Date field. I'm pretty sure that once the due date has passed, the to-do will indeed start to hurt you. (This didn't use to be the case but I believe has now been implemented, but I can't find confirmation.)