While it's very convenient for you to book as much as you can in case there is the 2% chance you may actually follow through with your plans, it may shock you to know that this method is not as convenient for those you made plans with. Yes, this is correct, other people might be adversely affected by your actions. You see, on the other side is a person who also has a life! And when you cancel, that leaves them with their own scheduling conflicts to face. That time making up your life? All the creatures of the earth have that. Cancel once and awhile- totally understandable. But when the pattern becomes predictable you become someone who sucks just a little more than you did the last time.
(This is on behalf of all of those disturbed by chronic cancelers, sponsored by people who care).
*Note: I personally get over chronic cancelers after the 3rd offense. Then I just agree to plans but make my own back-up plans based on trending statistics.