I have been using bitcoins for a few months now. And I guess there are some things which I think have caused me some difficulties. I only have two difficulties as follows.
(1) Price Changing Suddenly-- It really hurts and creates problems when rates go down and value of bitcoins decreases though being same in number of coins.
(2) 90% Shops don't accept bitcoins in my area and thats a huge problem for me as my btc usually stays lied in wallet.
We are well aware of both of these problems and trust me, as time passes by and as we will continue growing, both of these problems will slowly be disappearing. We just need to have patience and keep working hard as a community!