1) What if someone hacks and steal my bitcoin.
Too bad, really. It all boils down to what steps you take to secure your Bitcoins and computer. Its very easy to do so. Personally, I don't have an antivirus but I keep my Windows up to date and only surf and run programs that I know are safe.
2) What if government shut down bitcoin.
The probability is VERY low. The decentralised nature of Bitcoin makes it such that Bitcoin is almost impossible to shut down. You can make it harder for your citizens to use but you can't ban all the nodes from accessing your country.
3) What if I buy something via bitcoin and the seller doesn't send me what I paid for.
Unlike Paypal, Bitcoin doesn't have an escrow system due to its decentralised nature. If you want to be secure, use an escrow on bitcointalk, one that you can trust.
This list goes on.... What do you guys have to say about it? Why so much fear around Bitcoin? is it time to centralize the Bitcoin so that we could shop freely so that we could have purchase protection just like visa and mastercard Chargeback policy. Decentralization is good but it truly sucks.
Frankly speaking, they don't have a perfect system either. Merchants are susceptible to the loss incurred by consumers charging back when they purchase. The merchants often have to bear the loss too. If you can get a third party, you can use Multisig to secure the transaction such that the seller cannot run away with your funds.