[pjc50]

The kind of things I've seen reported on /r/bitcoin:

- lose key to wallet

- lose wallet due to inadequate backups

- lose contents of "brainwallet" due to weak password

- lose wallet/contents due to malware targeting bitcoin

- lose wallet/contents due to bug in client software (recommendations change frequently)

- send to merchant, defrauded in the old-fashioned way

- keep on exchange for trading, exchange collapses

- erroneously swap transaction value and transaction fee, or other fat-finger errors

- erroneously send to wrong or non-existent target address

[duiker101]

It's like dropping your phone in the toilet. You never think it'll happen to you... until one day...

[DennisP]

Many of these can be prevented by multisig and/or a hardware wallet with the seed phrase tucked away.

Sending to the wrong address can be fixed with smart contracts that associate addresses with easier identifiers. Swapping value/fee can be prevented with a simple safety check in the client software, to make sure the fee is reasonable.

[elcct]

We are still at the beginnings. With Bitcoin you are your own bank and some people are not used to have such responsibility and freedoms it gives.

[blibble]

one of the pro-consumer features of the regular banking system is that it is possible to undo mistakes

not possible with bitcoin

[elcct]

It is possible, but sometimes it is not. If you sent money to wrong account, bank can't just take it back from other party account.

On the other hand, I by mistake sent bitcoin to a wrong address and couldn't believe that someone who owned that address sent me all bitcoins back week or so later. There are good souls out there :)