Not a parent myself, but being the oldest of five [with a 28-year-spread between us...yikes!] has taught me a few things.
- Eventually, they will hit the rebellious stage. This is nothing personal. They still love you, you're still important to them. When they hit this stage, it means they don't want to be seen as a kid anymore, but don't know how to not be seen as a kid, and the first instinct is to cut off everything they did as a kid. If you can recognize that it's time and foster that transition, you'll save yourself a lot of headaches, grief, and a few years of wondering why they don't like you anymore.
- If you go along with the above but the actual parent(s) do(es)n't, prepare for one mother of a feud...I speak from experience here, treating my sister as an adult long before mom did. At best, they'll be jealous that they're not the central figure to the kid's life. At worst, they'll hate your guts.
- The worst thing you can do for a child's future is assume they're helpless or stupid just because they're young. Inexperienced, yes, stupid, no. The difference between 'No, you're too little to do that, go do something else' and finding creative but less/not dangerous ways to be involved is the difference between someone that will shy away from new challenges or take them head-on. Every potential "you can't" is a potential to teach.
- I'm forever thankful to my father for the above. Early on, he never gave me a blanket 'no, because I say so that's why' due to danger. He took the time to explain why. 'The stove might still be hot even if it's not glowing. *He holds my 4-year-old hand over a recently-off, but dark, burner* Don't touch it until you know for sure it's not hot', for example. Because of it, by age 6 I was able [and trusted] to do simple cooking, built models with an hobby knife, and grew up to be unafraid of learning by doing.
- The best thing you can do for a child's discipline is to be consistent. A child's job is to test their boundaries. A parent's job is to make sure they stay intact.
- Likewise, a toddler's job is to try and get themselves killed exploring their world. A parent's job is to make sure they fail at this task (without denying exploration).
- Cuts, scrapes, bruises, sickness, and tears are inevitable...and as much as it might hurt to admit, a good thing. I'm not saying to let your toddlers play Hansel & Gretel or eat piles of poo, but as much as we want to we can't put our children in an impervious little bubble. Not only is it impossible, but it's very, very bad for them. Being sheltered hampers their adult lives. Getting sick builds a hardy immune system. Eating (ultimately harmless) things they shouldn't builds a hardy digestive tract. Cuts, scrapes, and bruises hone the body's injury responses. Forcing a kid to live in a bubble, soaking the toys in bleach twice a day, etc, it's a one-two punch against humanity. "Kills 99% of germs" means 1% of germs survive...and the more times you wipe out the 99% of the weak ones, the more you're accelerating the creation of 'superbugs'. It's simple evolution...we're trying to commit genocide against them, they're trying to survive by adapting to what we throw at them. So the bugs get stronger...but since we're not exposed to them, we're not building defenses to fight back when we do eventually get sick.