The truth is that anything process you make to know bitcoin is a lesson, both the advantages of it and also the disadvantages of it, because in bitcoin, learning is a continuous process due to blockchain is very broad that you can't know about it within a short period of time, so if it's your first time to purchase a bitcoin and after purchasing bitcoin the price drops or collapsed in the market, that will give you the hedge to learn when to purchase and period you're not supposed to purchase bitcoin. So every failure or disappointment gotten from bitcoin is a lesson.
One mistake that really made someone can't forgive himself is sending a large sum all because of his fat finger. Funny I've seen few threads about this, just couldn't see myself having this mistake even if I have a fat finger myself. Either the guy is in a hurry doing it or his eyes is just not 20/20.
We can't doubt them, it may be that such things happened, but it's doubtable, because anyone who is funding a wallet you the exact amount or value you send and you will type the digits with your system button, except that you want to send everything in that wallet before you will click on MAX, so clicking on a max, it will push everything in that wallet and you definitely see the values of the coin and the change before you inputs your password, so it's difficult before someone could make such a mistake, except that person is not careful.
Checking the address while exchanging is very important. Basic knowledge of using a wallet. During each transaction, we should complete the transaction carefully so that you do not make any mistakes and the crypto assets do not go to the wrong address.
Theirs nobody that doesn't take precautions by crossing checking a wallet address before sending a bitcoin to an address they transaction is supposed to be done, sometimes if such mistake may occur it's due to over curiosity, we all know that every thing concerning bitcoin you most be careful of it.