Wikipedia defines common sense as “knowledge, judgement, and taste which is more or less universal and which is held more or less without reflection or argument”
Try to avoid using this topic to express niche or unpopular opinions (they’re a dime a dozen) but instead consider provable intuitive facts.
Lemme try my favorite way to explain the birthday problem without getting too mathy:
If you take 23 people, that’s 253 pairs of people to compare (23 people x22 others to pair them with/2 people per pair). That’s a lot of pairs to check and get only unique answers