So many things in life require an inordinate amount of work to achieve.....often times, the effort seems so burdensome as to not be worthwhile. Don't trick yourself into thinking this way.
Instead, stick to your guns and drive the point you seek to make home until you've achieved that goal. Then, set new goals for yourself and work to achieve the "barely impossible" again in the future.
As long as your goals are realistic, they should be achievable.