Habits are important, but restarting is more important. You will forget to work out, fail at your diet, upset a friend or coworker, or make a million other mistakes.
The quicker you get back up and restart the easier it will be. The longer you wait the more painful it will be to start again.
Next time you skip a run start get back into the habit quickly.
If you make a mistake, own up to it quickly and start work again.
You only have two choices: restart or never do that thing again.
If you want to run or climb or eat healthy or have a good relationship or whatever it is, start today, every moment you wait is lost.