I don't think they mean it literally, I often take them to mean "you never stop worrying about them" And I get that. I'm 37 with a child of my own, but if my mum knows I'm going on a trip she likes me to text her once I land/once I'm home, even though we live 300 miles apart!
My DD is 3 and (besides the tendency to leg it whenever she gets the opportunity and the very big emotions) 3 is the best year yet!
Her language skills have always been excellent, but we can have proper little chats now. She's funny and kind and her imagination is blossoming. She can take herself upstairs to use the toilet and we very rarely have accidents - I have actually stopped worrying so much about taking a change of clothes everywhere we go.
Disturbed nights aren't rare, but let's say they're 2 out of 7, and for us that is HUGE because this kid did not sleep through the night even once until she was 26 months old.
She is (mostly) reasonable and we can negotiate together. Gosh! The list just goes on! 3 is amazing!
And there are new things: friend drama at pre-school, testing boundaries, desperate to be independent, very loud emotions that are a reminder that she's still kind of a toddler. But it is easier, so, so much easier than the days of true sleep deprivation, having no idea what was wrong when she cried, worrying about every toy/crumb/pebble/grass/sand going straight into her mouth, stairs gates, nappies, buggy everywhere. They were beautiful days in so many ways, but this is a bold new world compared to the baby phase.
But I guess maybe the comparison needs to have an age limit. Comparing teens and toddlers is just too difficult. The problems and the joys are too different.
My daughter is a true sunshine personality at the moment, but if she has a difficult time in her teens/early adulthood, I know it will be worse than the newborn phase because I won't have control or the power to fix things like I did back then. I am willing to try whipping out a boob, but that will probably just mortify us both 🤣🤣