I'm sorry I made you cry

As I was sitting here tapping my keyboard trying to think of something to write when my second line rang. It seldom rings because....well, it's my second line and no one has the number.
Hello, I said. "Who is this!" came a terse voice. "I don't know, I can't see you," I said. I heard a laugh on the other end of the phone and then "I must have the wrong number."
I always say that when someone calls and asks "who is this?" Spanky from the Little Rascals did this one one of the old episodes. The principal called the Spankster's house because the latter was absent from school that day. The phone rang and Spanky said, Hello. The principal crossly said "Who is this?" Spanky said "I don't know, I can't see you." The principal who was not amused said this is principal Sam, now who is this? Spanky said "that's easy, you just told me you're principal Sam."
I am amazed at how funny TV (and movies) were back in the 40's, 50's and 60's and never was an "ugly word" uttered. The Beverly Hillbillies, Andy Griffith, Bewitched, and a zillion others kept us in stitches without degrading women, minorities, or others. The humor was not mean spirited. Had there been "cussin'" on our TV, it would have wound up in the yard. Momma would not have stood for it. She takes a dim view of a foul mouth. Even today she would whack at me with her walker if I made an off colored remark within ear shot.
I think dirty humor is easier. Comedians can utilize practically any kind of profanity, or make any group the brunt of jokes and someone will laugh.
I believe clean humor takes more thought. I'd like to hear your opinion on this topic...in fact, I'd like to post some clean jokes. If you have a good one, send me a comment. I'll start it off:
Knock Knock
Who's there?
Boo
Boo Who
I'm sorry I made your cry