When does planning interfere with achieving our goals?:

In one study, the authors provided participants with a to-do list of “virtuous activities” to complete over the course of five days; some people had one activity, but others had six. Half the participants were encouraged to plan specifically how, when, and where they would carry out the to-do list each day. “We found that specific planning helped people who had a single goal on their to-do list, but not people with multiple goals,” the authors write. A second study, which involved a computer task, yielded similar results.
Why is specific planning less effective when applied to a number of goals? The authors believe that planning reminds people of all the obstacles and constraints that stand in the way of achieving goals.