My pleasure is a warm reply to being thanked. It was my pleasure, my pleasure entirely.
Where don't mention it makes the favour small, my pleasure says it was gladly done. It is common in service and does not sound false when it is meant.
1phrasemy pleasureA warm reply to being thanked.
“He took the bags up and said it was my pleasure.”
my pleasure is a phrase.
Practised in Small Talk & Everyday Phrases