Oh, it didn't end perfectly. His wife was the office manager, and grew to resent me immensely for being perceived as inspiring her husband's change in behavior. Less smoking, more walking, dietary changes, etc. Unlike him, she had less than zero interest in any of those lifestyle changes and it created strife, which palpably transfered to me all the way up until I eventually quit.

There's a very serious cost to living with the cynical perspective your comment expresses. If you think that people will only change when you have authority or leverage over them, and that they will always ignore reason, you'll pass by hundreds of chances to reach equitable mediums over your life, and get nothing in return except a little saved inconvenience of never opening discussions with a less than 100% chance of success.