Board Thread:Arrow discussions/@comment-807326-20170518025511/@comment-26062541-20170524051111

And even then he might go back in time and the speed force would punish him in some creepy and cruel way that may be  ironically  of his own  creation(personal headcanon).Black Siren had plenty of chances to not do what she did, Felicity didn't and chose the needs of the many over the needs of the few, and has to live with that every day. Basically Felicity feels bad she couldn't save lives, while Black Siren did not.