It's an interesting contradiction of enneagram and MBTI that so many SPs are 7s. On the surface they seem to correlate quite well, but 7s are all about planning, i.e. thinking of all the other stuff you're going to do. That is true for me. I plan, sure. I have a planner, I make to do lists, I'm always taking notes and making schedules...The truth is though, I rarely accomplish half of my to-do list, I only write in pencil in my planner, and most of my schedule is a pipedream. I think it's fun to pretend I'm going to do something at a certain time and imagine how much I could accomplish if there was a start and end time. It just isn't in my nature. I need a planner to function, also because I am not naturally organized or premeditated.
A stimulating diversion, or a bit of fleeting pleasure/enjoyment will always win out over the things I ought to do. I like to keep my options open. Planning is just a fantasy.