I have one Grandson who just turned three and he is the "light" of my life!
Truly, it's like having all the "good" times of parenting without the bad times (kid crabby, kid has nausea, kid won't sleep, kid gets sick when something important is going on in your life, etc.)
The only downside is that my little guy is far away and I only get to see him monthly if I'm lucky.