I remember that small kid energy like it was yesterday. Everything they do is entertaining and fun and just so damn cute. Their view of the world is exciting and fresh, which makes you forget about the adult world for a little while.
So...are you grandparents that spoil the kids, or do you actually listen to what the parents want you to do? My father-in-law - I kid you not - couldn't wait until my kids were old enough to eat french fries. I think he tried giving them to my daughter when she was 1 year old. To this day, he and grandma still stop by every week to drop off junk food for my kids.Today, it was Burger King and Oreo cookies.
We've given up arguing with them about trying to maintain healthy diets: they don't care, because bribing the kids (to like them better)
works!

I love both of my in-laws, but this is a case where we agree to disagree. So, we make sure that our kids eat healthy the rest of the time, and we look at the mid-week junk food delivery as a fun break.