Nothin' wrong with some friendly father/son trash talk -- just ask Ken Griffey Sr., who took a shot at his famous son yesterday ... and hit him where it hurts.
The 64-year-old Cincinnati Reds legend was at an event for National Hot Dog Day (seriously) in Washington D.C. yesterday when we asked what it was like having a famous son with the same name.
That's when Senior took a dig at "The Kid" -- telling TMZ Sports, "You always want the best for your child. So, if he's better than me, that's fine. Just remember, he's got all the home runs ... I'VE got all the rings!"
For the record, KG Senior has TWO World Series rings. Ken Griffey Jr. has zero.