Of course there are hard bits (DS vomiting all through the night when he was three years old was particularly unpleasant - I didn't have a spare sheet, towel or T shirt to fit him in the house for 24 hours!)
DS didn't sleep for more than four hours each night until he was four years old and sometimes I was so tired I was in bed at 7pm.
But, he's now 12 years old and thinking back over the years all the good things include...
His first word and first step.
Reading stories (endlessly sometimes which could be tough when you just wanted a cuppa and some grown up TV!)
His first day at nursery when he ran out shouting he'd had fun.
His first day at school when he asked if he could go back the next day.
Holding hands on the way to school - he'll still hold hands occasionally.
Seeing him at sports day - DS has a heart condition but his team mates would (and still do) cheer him on even when he was a very definite last.
Watching/helping him learn to read and write. I'm still amazed at how the little bundle that couldn't even feed itself suddenly learns to read, write, do maths, sing, run etc in the space of 3 or 4 years on this planet!
Seeing him build really good friendships with wonderful kids who became part of our family.
Seeing him pass his 11 plus and watching him now as he goes into year 8 at school. The stuff he knows! We watch Eggheads/The Chase/QI etc and he keeps up with the questions. He's even managed to get a couple of answers on Only Connect (which I think is something at 12 years old).
So yes, it is hard. Yes, sometimes it is disheartening. Yes, sometimes you hanker after just a few hours of 'how it used to be' when you could just book a weekend away without packing baby stuff. Or sit on a beach reading a book then napping or swimming. Or sit in a restaurant on a warm evening on holiday until closing time chatting with a bottle of wine without thinking 'past his bedtime, we'd better go' or getting a 'mum/dad come and play; I need the loo; I'm hungry'.
But it's also wonderful looking at the person that emerges as your child grows and realising that you've had a part to play in that being. You're making them what they are, in part. Every year I enjoy meeting my 'new' DS as he changes. I love every single one of them I've met so far but I do enjoy learning about the 'new' one as he begins to become the man he's meant to be.