You're leaving your company to start a new job. You visit your boss to say goodbye on your last day. You tell her this to show that you appreciate how much she has helped you.
You drink alcohol most nights with your dinner. You're discussing this habit with a friend who doesn't drink much at all. You give this reason why you drink that often.
You're telling a story about a silly mistake you made. You thought you couldn't get into your house, so you spent the night in a cheap hotel. This is the punchline of the story.