It's what every parent gets excited about and non-parents look at them and think "why all the fuss?" Honestly, I don't know why. Having a baby changes your perspective on the most automatic or menial of actions. As a Father I can safely admit that I took smiles for granted until I saw my son smile for the first time.
In the first months almost everything is a "first." Its so exciting to experience it as a parent. The first latch (to the breast, moments after his birth). The first night home; which was emotional, exciting and a bit scary. His first bath, his first blanket. I could write a list a mile long of his firsts.
I think this past year has taught me to appreciate those little things. To watch him closely for each and every first and praise him and show him how proud I am. I remember his first solid meal; feeding him tiny spoonfuls of pea purée. I watched him as he pondered each bite and had the most adorable expression on his face. He loves peas and did from the first time he tasted them. Now every time I feed him i remember that first spoon full of liquefied peas and I smile.
I think the firsts are things that modern fathers lose out on the most. We think that because we are men we shouldn't care bout "those little things" that babies do. Well let me tell you that this is far from true. Your son or daughter will love and appreciate you if you just watch for those firsts and praise him/her for them. Show your child that what he does matters to you. The simplest thing done for the first time, to a child, is an amazing accomplishment that should be cherished.