This particular DoF focuses on who was the greatest and who was the worst President. Now, if your understanding of humanity is no more evolved than "him good, him bad," this DoF makes perfect sense.
But if you think about it and if you read even a CliffsNotes version of history, how many of us can be summed up as "him/her good, him/her bad"? In fact, how many of us want our lives to be summed up that way? Especially since I can point to some past deeds of mine that were good and some that were bad and many that were debatable. In essence, I'm neither good nor bad. I'm human. That's all. Simply human.
So take our Presidents. Unless you're Ron Paul, you probably hold Abraham Lincoln in high esteem. In most of our minds, Lincoln falls into the "him-good" column. But Lincoln did much that was debatable at best, including major violations of Constitutional law that make both Bush and Obama look like pansies in the "Shredding-the-Constitution-to-Pieces" department.
Then, there's Richard Nixon, who is Lincoln's polar opposite and universally hailed as "him bad." Yet Nixon's crimes were rather tame in comparison with some of the shenanigans going on today (and in comparison to some of the actions of his nemesis, JFK, another universally hailed "him good"). Suffice it to say, the NSA has violated more personal space than Nixon ever did. And lived to lie about it longer than Nixon ever did.
But "him-bad" Nixon was also a pioneer in environmental protection and other legislative measures that most of us would throw into the "this-good" column.
Washington, another "him good," had a major tyrannical streak in him. There's a reason why the WashPA area holds a Whiskey Rebellion festival every year, since "him-good" Washington decided to forgo the Constitution when the ink was barely dry to trample all over citizens' rights because their protest against the newly enacted Whiskey Tax didn't suit the ambitions of the federal government (or his private business interests). Washington, though, also did many incredibly impressive deeds that warrant our esteem and the title, "The Father of His Country."
We could also talk about FDR and his Japanese internment program that was being conducted even as he steadfastly and bravely guided this country through a horrible war. We could talk about Bush's misdeeds in Iraq, even as we talk about the incredible work his policies have done to curtail the spread of AIDS in Africa.
Go down the list of our 44 presidents and you can play this game of "that good, that bad" with every single one of them and their actions in office.
So, what am I getting at? This DoF of which president is good and which president is bad is dumb. Dumb, dumb, dumb. It reduces our presidential history to pre-K levels of human understanding.
I submit instead: There were (and are) no good or bad presidents. There simply were (and are) human presidents.
When you look at our presidents as human beings, the discussion becomes not so much about great and least great but about understanding ourselves and learning how power can cloud and clear our judgment and lead us to deeds that are good, bad, but more often than not in the gray, misty ethical middle...
tl;dr: Debating who are the greatest and worst presidents is one of our more futile lines of discussion, since all presidents have done good and all have done bad. Instead, we should focus on the humanity of our leaders and learn from their mistakes and their successes.