At three years old, you can sit knitting on the bench at the playground while your child climbs a mountain of a slide 5 times his height without so much of a blink. You're confident he can find his balance instinctively and if not, he can handle a bit of a tumble better than you could.
You can sit next to him as he feed himself lunch, probably feeding you too in the process. Sometimes you can even swing a quick shower while he's snacking. He can pour himself a drink from the water jug on the table, saving you from having to get up.
Sometimes he reads himself a book, build himself a rather nice looking 'pirate boat', or clicks himself a video from the Cbeebies website.
He can clean up after himself. Oh in fact, he enjoys 'tidy up time' a whole lot more than you do.
He doesn't eat sand, or paper, or leftover food from under the table, or chokable buttons under the sewing machine.
You can have a real conversation with him. Not only will he listen, he can also respond with appropriately placed words like ' Oh I see....'
You don't have to have a heart attack every time he climbs the table or the kitchen bench or anything with remotely sharp edges. After about a million bumps and bruises in his lifetime he is now pretty savvy at threading the hazard zones.
Of course by the time you find the wisdom to appreciate all this, enter child no 2, in all her cheeky, no-regards-to-danger-whatsoever self. There is nothing like having another baby to give you the wake up call you need as to how under appreciated you firstborn is. Oy.