We as grandparents aren't sterling examples of what should be. Once we were our kids. One of the characteristics of becoming an adult is Post-Adolescent Amnesia. This is when the young adults deny any recollection of having sex or knowing anyone who smoked marijuana.
As grandparents it seems that we forget the divorces, the arrogance, the arguments, the pettiness, the lust for revenge, the extreme behavior that we engaged in. The kids have sort of survived the outright torture and confusion that were visited on them (not necessarily by you or I). It's not really productive to dwell on this too much, a little forgetfulness will serve us well.
We have a different perspective now. The passion and hormones have receded to a dull roar, a little history and perspective have given us a little "wisdom" in maturity. In the background we see are the same unfortunate things happening to the grandkids. Parents do irresponsible things: desert, have live-in companions (who may not have the same interest in the child's welfare as you do), and make lots of mistakes. So you can't be too hard on the kids even though it seems a size ten shoe would fix a lot of things. After all, this is your genetic investment in the future.
Some of us are pooped and just want a quiet garden in a quiet place. Some of us think kids playing, arguing, crying, learning is the sweetest music in the world and can't get enough. Still others, having their druthers, would druther be in Philadelphia with the W.C. Fields the fat actor with the red nose. But, one kid has split, the other leaves the kids alone and unsupervised because they're still kids themselves or just haven't gotten the brass ring yet.
What ever it is, the kids don't have supervision, they're running around the neighborhood and it doesn't take a weatherman to see which way that wind is blowing. So, we pull up our stomaches and get ready to fight to protect the kids. They kind of tug at your heart anyway and for a change you have the time to spend with them. Then there are the other grandparents. The morons who boast that their kids never went to college and look how much they make.. It's enough to make my eyes go out of focus, that's what.
Now it's a different game. The other grandparents have their interests to protect. The kids are just "doing their thing" and the grandkids are just pulled and pulled.. For me it sounds like history repeating but now I'm the grandparent.
Fortunately, most of the other kids are doing ok. Bright happy kids with every moment of the day filled with soccer or trumpet or violin lessons. I'm not even sure the kids realize there is trouble to get into. "Free time" is an abstraction: they have heard of it but it has real meaning to them. Their parents find time to make this happen.