“A nail is driven out by another nail; habit is overcome by habit.”
“S is for SCARY! Fear is driven out by action! Bad habits are overcome by good habits.”
“Fight like a man. Habit is overcome by habit.”
“Knowledge—like a nail—is made load-bearing by being driven in. If it's not driven deep enough, it will break when any weight is put upon it.”
“Only a habit can subdue another habit.”
“Of all the forces in the universe, the hardest to overcome is the force of habit.”