Most likely, these two phrases are already in your vocabulary – especially if you’re Canadian. Often “I’m sorry” and “excuse me” are used interchangeably, but there are times when it is more appropriate to use one over the other.
For example, Emily Post’s Etiquette suggests that “excuse me,” “pardon me,” and “I beg your pardon” (this last phrase a rarity today)
all express your awareness that you’ve inconvenienced someone else.
Whether you bump into someone, interrupt someone, make a request, acknowledge an error, leave a conversation, get up from the table, or acknowledge any other faux pas (such as burping), an “excuse me” politely shows you recognise that you may have inconvenienced someone.
Debrett’s A to Z of Modern Manners defines the situation in which an “I’m Sorry” is best:
A sincere apology should always be offered when your actions have had a negative impact on other people.
When you take responsibility for your own actions, it’s difficult for people to stay angry or upset at you. It also lends credibility to your character as an honest and respectful person. Even if you don’t understand why you should apologise, giving a sincere admission shows that you respect the other person’s feelings. (Manner Reminder: that’s what manners are about: respect!)
Although it is common for the English to apologise for other people’s actions, and it’s the Canadian way to apologise for everything – resist that urge. Constant and needless apologies devalue the word and lessen the impact of a genuine and heartfelt phrase.
Bonus Tip: Admit the fault as you apologize. E.g. I’m sorry I dropped the cup, I’m sorry I hurt your feelings, I’m sorry I was so late are all more effective than solely I’m sorry.