Kids... Or a lack thereof.

So now that I am married and my sister has had her first child, I feel as though the topic of kids comes up more often.  Have you ever noticed that once you are married everyone just assumes you're going to pop out a kid or a few?  Like your marriage isn't complete without one.  You should hear the comments if your answer to "so when are you having one?" is "never." Even when you include a whole list of well thought out reasons why kids aren't for you, there's always a reply along the lines of "ohhh that may change."
I once even had a conversation with a woman explaining how I didn't want kids whose reply was basically that I would probably change my mind like her sister who never wanted kids but changed her mind... and  went on to add that now that she thinks of it her sister is just not a good mother.  Um, yes, thanks for proving my point!
I will be perfectly honest, I'm not completely sure why people want kids in the first place.  Childbirth and pregnancy are uncomfortable and painful.  Kids are a lot of hard work that you can't take a break from.  Most people don't even have time for their kids really, and pay to make them someone else's responsibility at least a part of the time.
My own personal reasons for not wanting kids are numerous, and one of them is that I love my job, I intend to continue doing it for quite some time, and would not like the idea of sending my kids to daycare.  I don't live close to my family, so I do not have the option to have family watch them like my sister does living close to both our parents and her inlaws.  I just personally don't feel child care is the best place to have a child for such a length of time almost every day.  In addition to being expensive, I would just not feel good about myself if I had kids in daycare.  Since I have already put a lot of time and heart into my profession, and those in my position are desperately needed, it makes sense to me to focus on that.
Also, I am in need of a lot of down time.  I like getting home from work and sitting on my ass.  My husband likes getting home from work and sitting on his ass.  That would not happen with kids.  I like to pursue interests outside of work, I swing dance and go to gymnastics classes and those are things I may not have the time to do with kids.  Some people see this as selfish, I know, not wanting kids because they would get in the way of me doing what I want.  But it's entirely the opposite.  I would be selfish if I decided to have kids and still did everything I wanted anyways despite it interfering with quality time with my kids.  I know lots of people like spending their time with kids (particularly their own) and are perfectly happy devoting all their free time to them.  I am not that person.  I worked hard to be a financially stable adult with the freedom to do whatever I want (within budget) whenever I want (work schedule permitting.)
And about that financial stability thing... KIDS ARE EXPENSIVE!!  We don't need that.  So much added stress.  No thanks!
I continue to go back in forth in my head on whether or not I'd even be a good mother.  On the one hand, I have a lot of experience and training and know my kids would be well behaves- IF I ever got up off my lazy butt to deal with them appropriately.  I'm just not sure if I'd be that mom who sat there and yelled "stop that!" from the other room without ever actually DOING something.  And I can't stand moms like that.  So I certainly don't want to become one.  And if I were to become one, my kids would be those annoying bratty kids that made me realize maybe I don't like kids all that much in general.
And of course, my husband also doesn't want kids.  He just doesn't like them, is what he says.
So, why do people want kids?  This is an answer I don't have many answers to.
To take care of them when they are older?
To have someone to love?
To have something to take care of?
To live vicariously through them?
Because god said they should?
Because society/family/etc said they should?
To see what the combination of genes with their chosen person looks like?
A crazy experiment?
Biological, evolutionary instincts?

If you have kids, why did you choose to have them?  If you have not, why not?  Would love to hear other peoples thoughts!

~Katy