An unforced error is
a missed shot or lost point (as in tennis) that is entirely a result of the player’s own blunder and not because of the opponent’s skill or effort
often happening because of impatience; inattention; or taking unnecessary risk.
In other words, completely preventable.
Life, I find, comes in peaks and troughs.
There are times you feel like nothing gets you down; and opportunities are everywhere. In these cases, play an offensive game and go get ’em.
And then there are other times when nothing seems to go right; and traps are everywhere. In these cases, a defensive game may be your best bet.
Sometimes when the world’s moving backwards, progress means standing still.
Sometimes that best we can do is simply to make no unforced errors, and leave the offence till a little later on.