Your biggest mistake is thinking you’ve done something wrong. A safe landing is not judged on the firmness of the touchdown.
Take the opportunity to educate the cabin crew. Most of them have little aviation knowledge. Explain to them that a landing within the touchdown zone is the desired result, whether it is firm or not, and it’s better to land firmly in the touchdown zone rather than float and chew up half the runway to pull off a greaser, especially in wet conditions or on a short runway.
If you smile and laugh it off you just perpetuate the myth that positive touchdown = bad landing.