Doses and Don'tses

For the record, per the Chicago Manual of Style (via this webpage), the only times you use an apostrophe to pluralize are:

• Lowercase letters: "Mind your p's and q's."
• Uppercase letters only if there would otherwise be confusion, such as with I and U (but in that situation, be consistent across all uppercase letters).
• Abbreviations that have mixed case or interior periods. "Too many Ph.D.'s."
• If you are using something that is not usually a noun as a noun, it's very occasionally the right choice, such as "maybe's".

In all these cases, the apostrophe is strictly there to avoid confusion, not for decoration.

Roo: Daughter Knows Best

Monday, for assorted boring reasons, I was the one to drop Roo off at daycare, instead of her mother. We walk up to the door, and I ring the doorbell.

"Daddy, knock."
"I rang the bell, sweetie."
"Daddy, haveta knock."
"No, dear, that would be rude, I just rang the bell."
..."Daddy, knock!"
..."Okay, it's been a minute, maybe you know something I don't." [knock, knock]
Daycare teacher opens door, "Oh, good morning! Did you know the bell is broken?"
"No, but my daughter did..."