An old lady fell down the stairs and broke her leg. The doctor put it in a cast and warned her not to walk up and down the stairs. The leg was slow in meding. Finally, after six months, the doctor announced it was all right to remove the cast.
"Can I climb the stairs now?" asked the old lady.
"Yes" answered the doctor.
"Oh, I'm so glad," she smiled. "I'm sick of climbing up and down the drainpipe all the time.