I cant believe that this person sent 0.1 Ether with 2,100 Ether transaction fee. I am pretty sure that this person is crying out right now and just shaking his / her head repeatedly. What will you do if this happens to you? How will you comfort your self at a time like this? 2,100 Ethereum for transaction fee really is a big amount and unfair on that person but a mistake was already made. I hope that he can contact the miner who processed that transaction for reimbursement which is I think possible. Look on the reference below.
https://etherscan.io/tx/0x1f73b43dc9c48cc131a931fac7095de9e5eba0c5184ec0c5c5f1f32efa2a6babIts not something problem with blockchain,the user who wrongly entered the value and resulted losing all his money.It is very huge amount to be lost but when someone in that much hurry then don't do this much worth of transaction because money is important in this world.