I have 4 children, aged 14, twins of 11 and an 8 year-old. I love them dearly but now I think 4 is too many (which ones are too many varies depending on the day - lol)
I think that every experience is balanced by equallly strong negative and positive feelings. Looking back I found the toddler phase the best and the worst because I found it very hard to be calm and neutral with a toddler; either I was consumed by intense feelings of love which urged me to want to eat my child almost or else I had to exert immense self-control so that I didn't strangle them. Once I locked myself in the bathroom to force myself to calm down so I didn't hit them (this was with the twins which are an extra-special challenge). Peacefulness is not a frequent state with toddlers. As they say, no parent ever loved their child so much that they weren't glad to see them asleep.
Now that my children are older, my relationship with them is calmer, we are more equal but I can still see that there is a difference between how I love my 14 year old and my 8 year old. I still have waves of passionate love for my little one but I look with a contented sense of pride and love at my big one.
One of the hardest things for me was to trust my children, and yet I think it's essential because we all need to follow our own instincts and beliefs in life and not abdicate that to others, not even our parents. And that starts very young. My twins are very physical and eternal acrobats. Even when they were litle in the playground and they wanted to do something that I thought was dangerous I would ask them if they felt able to do, to examine the situation and decide if they could. If they said yes, then I let them do it, with my heart in my mouth. Of course this is only in a situation when they need to assess their own capabilities like going down a slide or climbing a tree, not when outside factors are more important, like crossing the road.