i love this cartoon! i came across it from a comment on a blog post about apologizing too much and found it lovely. a good way to be more positive and to impart some agency to others, instead of taking it all on yourself.
i use 'sorry' a lot, many times as a way to say 'excuse me' or 'if you don't mind'. in many of those instances, using 'thank you' would work just as well, and so i should try it. it would make me more assertive i think, which is sorely needed!