n.
the habit of telling yourself that just one tweak could solve all of your problems—if only you had the right haircut, if only you found the right group of friends, if only you made a little more money, if only he noticed you, if only she loved you back, if only you could find the time, if only you were confident—which leaves you feeling perpetually on the cusp of a better life, hanging around the top of the slide waiting for one little push.
From just, only, simply, merely + jousting, a sport won by positioning the tip of your lance at just the right spot, at just the right second. Pronounced “juhst-ing.”