I don't necessarily have a favorite child, but I do think that it's naive to think that our parents never had a favorite occasionally. I definitely have one child more like me in behavior than the other, but they both frustrate me equally and they both have my unconditional love.
Sometimes I feel more in tune with the child that is more like me, because I know where he's coming from. Sometimes I also feel frustrated, because he won't do what I want him to do and he's "like me" when he gleefully runs from my requests knowing that he's spoiled enough to get away with it.
I also love the uniqueness of my other son. I love his weird little quirks that are so unlike me and how he doesn't meet any strangers. I love that he (generally) will obey when I ask him to do something. I also get really frustrated when I can't understand why he does certain things or acts a certain way. I also get frustrated when he keeps asking why, 1.4 million times a day (although I may have done that when I was a child too).
It makes me wonder sometimes what God sees in us. He obviously doesn't have favorites, but I wonder if He enjoys the ones He's had to work the hardest for or the ones who work hardest for Him. I wonder if He enjoys the curious ones more or the ones who obey without question. I wonder if He loves the ones who yell at Him and argue their point or the ones who yell at themselves for messing up yet again. I think that's why God gave us free will, He loves all of our differences and idiosyncrasies. It makes up for the frustration I'm sure He feels when we make the wrong decision.
He loves us, but He doesn't always protect us. He loves us, but He doesn't always give us exactly what we ask for. He loves us, but His ways are not our ways and His thoughts are not our thoughts. Just ask Job, or read Ecclesiastes, or any of the gospels. His love is there, through the whole Bible, but it may not be what we expect.