[darick]

I would argue that the difference in phrasing is what makes OP come across badly. "I'm glad I didn't do what that person did" just evokes satisfaction with your decision, perhaps relief that you made the choice you did. Saying you felt "so smug I didn't do what that person did", definitely comes off worse IMO. Now you are not just happy with your choice, there's this sense of self satisfaction/superiority that's a bit unsavoury.

[jvanderbot]

That is true, but a generous interpretation of the post leaves plenty of room for a benign intent.