I do think Dawn's annoying and whiny and all that but it's just... She's my age! Though I'm not really like her, I do kinda get her sometimes.
And in S5 (especially in the beginning) they made it seem like she was only 10-11 years old. Which is kind of offending if you're the same age.
Also in S5: If I would've found out that I was created by some monks and that I'm only six months old, I would've freaked out, too.
Of course there are some moments where I'm just thinking "Oh God, please just shut up for once!" and although she's not one of my favorite characters, I still like her.