DS is a spirited boy in a number of ways. He requires a lot of one-on-one time and has a ton of energy. He requires a lot from us as parents...and I mean this in a good way. I also think it has to do with our parenting style. We watch very little tv with DS and try to do fun activities when we are home on the weekends with him, since DH and I work full-time. So..during DS's waking hours we are pretty much engaged with him the entire time. I have tried to do a few projects here and there, but DS wants the attention, so I stop what I am doing.
My point is that I sometimes find parenting exhausting. Again..in a good and wonderful way. If people ask when we will have more children I say not until DS is 4, because he requires so much of us. Sometimes I get wierd looks like I can't handle this job of being a parent.
Anyways, I just hope I am not alone in thinking that being a parent and giving 110% takes a lot out of you.