Sitting here, alone on my island, I have plenty of time to think. I think Gollum would have liked to be like everyone in the upper-middle class. At some point, he found out that all he really wanted was to have a very good salary, a nice (big) house, not more than two children and wife who worked and also made lots of money. I think he resents not having this "ideal" of society, another thing which makes him bitter. Unfortunately, this is something Gollum can never have, or at the very least he will have to wait a few years before he comes close.
Ahh, the burden that weighs him down gets heavier as the years go by. It is a horrible thing to carry, yet he cannot let it go. It consumes him.
I , on the other hand, do not need material riches. I could live simply and with little, as long as I am surrounded by friends, for as long as I live. Which is why I do not mind my island so much, only the solitude sometimes. Gollum cannot understand this in me and it irks him. But I am my own person, I do not need another person's approval.