Grandpa isn't grumpy, he's just brutally honest. "Sometimes being too transparent can be a bad thing". Yes, because people will call you hater when their widdle feelings get hurt, but gramps is only telling the truth kids. He's keeping it real, yo.
It's a bunch of snappy replies working hard just to lead up to a pun, but what they hey, grandpa is funny and the house location is gorgeous. Well done, scout.
-"Grandpa, when did you know grandma was the one?"
- "When her sister dumped me."