after a few weeks playing with bitcoin, for me, the biggest problem are the FEES.
People keep spreading the wrong message that bitcoin fees are cheaper than fiat-c, and sometimes people says that bitcoin don't have fees.... BUT in fact, i never paid fees in fiat-c transactions, they are free in europe, and in bitcoin i am paying fees in every transaction... I am playing with some wallets, moving some bits from one to another and i pay fees that are bigger than the amount i am transferring! this is a huge NO for new users.
People here in europe are accustomed to free transactions and when they see the fees in bitcoin, they turn down bitcoin world. it is very sad

I am a bit disappointed too, if i am honest

Fees might be low to zero to send in your own country but not worldwide. Besides, for most bitcoin transactions you can send for free as long as it's not dust. I have sent many transactions without paying any fees though I normally add a little something to help the network/miners.