If you're the person across the table, you don't really know when to stop saying "Bless you." After awhile, you wish they'd sort of just knock it off.
See, for example, the James Bond film Thunderball.
Yoo-hoooo! Be a doll and add a funny thing to do.
Dude, do you think she'll get it? See also 80's.
Oops! The higher the number was before you destroyed the record, the funner it is. See also Work.
...and thus upsetting the known order of the universe. See also Candy.