A bad habit
I overheard a friend telling his pal, "I can't break my wife of the habit of staying up until 5 in the morning.""What is she doing?", the pal asks."Waiting for me to get home."

A succession of generations
The village blacksmith finally found an apprentice willing to work hard at low pay for long hours. The blacksmith immediately began his instructions to the lad, "When I take the shoe out of the fire, I'll lay it on the anvil; and when I nod my head, you hit it with this hammer." The apprentice did just as he told. Now he's the village blacksmith.