A student went to his meditation teacher and said, "My meditation is horrible! I feel so distracted, or my legs ache, or I'm constantly falling asleep. It's just horrible!"
"It will pass," the teacher said matter-of-factly.
A week later, the student came back to his teacher. "My meditation is wonderful! I feel so aware, so peaceful, so alive! It's just wonderful!'
"It will pass," the teacher replied matter-of-factly.
(taken from here)