Newborn, so far. Until DD sat up unaided (4 months I think?) she was possessed by demons, miserable every single second, barely napped without earth-moving effort, and seemed to hate being alive. After that, from about five/six months to 2.5 was fine, she was funny, responsive, easier.
Now, at 3 1/4, she is a bloody pain in the arse. Argumentative, boundary testing every second, bossy, rude. We are sitting on her for bad behaviour, but some days it feels like all I do is warn her of consequences, impose consequences, wait out the tantrum/screams, quick cuddle and start again. Oh, and play endless dull games of HappyLand never were toys so ironically named. However, when she's being easier, she's lovely, funny, loving, and kind. She shares well, and has a soft spot for smaller kids which is adorable. I also adore watching her learn, it's like watching a sponge swell with water. Sometimes, when she's pushing boundaries, like asking endless 'why is a horse' questions at bedtime when I've told her to hush, I have to bite my lip hard not to smile at the sheer moxie and enthusiasm.
I actually can't wait for teenage years I know, I'll regret that as I think it's such a fascinating transition, and want to help DD go through it with her self esteem intact, if possible.