These past 5 weeks I have decided that the world is designed for having two children, but can be modified to accommodate more than two. I say this because I was able to juggle two kids on errands and I have two hands--one for each of them My 4 year old would walk while my two year old sat in the cart. I still had the cart basket to put in all my items. Now that I have three kids, it takes a little more juggling to accommodate all three kids. Especially when one is an infant and another is a wannabe independent two year old. My four year old is great and is a big help on my errands.
When I go shopping the infant carseat rests in the front of the cart where my two year old used to sit. Now I have to be more diligent in keeping an eye on her and making sure she doesn't run off. Everything in the store is simply too tempting for a two year old to: a) stay nearby and b) not touch.
I'm grateful that the two of the stores I go to most regularly have modified a couple of their carts to accommodate all three kids. I can put the baby in the top front part of the cart and there is an extension with two seats that my older two can sit in while I go shopping.
I do have a sit and stand stroller, but I've yet to add the infant bar so I haven't been able to use it for my youngest two. I really need to add that infant bar so I can cart the two of them around when we go to the mall or any other place without a shopping cart. Another thing I can do is use the new infant carrier that my mother-in-law gave me (thanks, Mom!). I can put the baby in it and have two hands free once again to attend to the other two kids. By the time I have another baby (if I have another baby) my eldest will be able to do even more to help me :)
Fortunately, my oldest is very independent and can do a lot of things himself---like buckle himself in, or hold hands with my middle child so that she doesn't run off, or stay nearby to give Mama a hand. It's a big help!
So while I think the world is designed for two kids (it takes at least 2 players for a board game, carnival rides usually accommodate just two people per car, I only have two hands, four doors on a car and then you have to go allllll the way to the back of the van if you want to add more people, most strollers are singles or doubles, etc) there are ways to modify the situation to make it more ideal for the parent who has more than two.
So my friends who are considering having more than two children, it's definitely doable to operate in a world that is seemingly designed for a family with only two kids ;)