good question....I've got 4 great lovebirds....my peachfaced ones can be temperamental at times though...they are wonderful birds and then every once in a while I get a good bite, too!

If I analyze it, there is always a good reason ( at least in their minds.) Usually I notice it happens when they are playing with me and overly excited...sometimes it's when I ask them to go back in their cage and they aren't ready...sometimes, they are just a bit grouchy ( I can relate.)
In other words, birds bite. Not always, but every once in a while....I mean, really, it is their ONLY way of showing displeasure. better than a cat peeing on your bed!

Still, it can be annoying and hurtful, so tell your little fellow in a stern but not LOUD voice "NO"..."BAD BIRD". and try not to get too exasperated over it...you don't want it to become a way he knows he'll get your attention...whether positive or negative.
Is it possible to be TOO bonded? Perhaps....but as long as your baby isn't displaying any bad behaviour or showing negative consequences...ie: humping you hand and such...I wouldn't be too concerned. It's wonderful to have a close relationship with such special creatures.