Scrooge made many mistakes Down below you will find a few examples.
First memory - when Scrooge was younger, he was alone for Christmas, this made him regret being harsh to the caroler that was outside his door the previous day. - Scrooge would remain alone
Second memory - the ghost reminds Scrooge of his sister Frannie who had died and left only her son - Scrooge regrets his harsh treatment to his nephew (Frannie’s son)
These two examples show that Scrooge made many mistakes and the ghost took him back to these memories to give him a second chance to redeem himself.