they grow up so fast??

Everyone says that time flies and kids just grow up too fast.
Does it really? Do they really?
I'm not so sure I agree with this. I felt like the first year of the twins' life was going by incredibly slow. Every day was so difficult that I just remember saying over and over "I can't wait until they turn one and can walk." Then after the first birthday came and went I said "I can't wait til they turn two and can talk and feed themselves."
I look back at my kids' baby pictures and it does feel like another time. A different world and one that I feel I was barely present for. I look at the pictures and think "I hardly remember them being so small". I think that's what people mean by them growing up fast; the fact that they hardly remember the happy moments of those first few years. But is this because it goes fast or because it actually goes dreadfully slow and you're so freaking busy in the day to day caring of a needy infant and simply in survival mode that you are not able to take a single second to step back and truly enjoy their cuteness?
I tend to think it's the latter. It's easy to look back at baby pics and videos and think "oh they were so cute and sweet" but if we let ourselves truly stop and think about what that time was like, do we really miss it? I know I don't. Constant crying, waking up at night, gassiness, fussiness, eating every two hours, clinginess etc...
They were sure cute but it was also sure miserable! It didn't go fast. It went slow. I couldn't wait to get to the point I'm at now. I actually have time to freaking blog!!!
Yes, it is a blur... I hardly remember the details of them being babies, but it's not because it flew by, it's because I was too busy to remember any of it.
Grandparents say that having grandkids is so much better than having kids. I'm sure this is because they are not so busy with the day to day responsibilities, so they are able to truly enjoy the moments that they were not able to as parents.
I personally dislike the infant stage most. I LOVE when they get past two years and I really can enjoy them because I'm not so busy caring for their every need, and time finally stops going so dreadfully slow.