Fascinating thread, 5 stars and one of the reasons AC is also known as 'Always Cool'.
It's very subjective to pick the 'greatest' president, just like it's subjective to pick the 'greatest' heavyweight boxing champion. One can say Ali would have beat Joe Louis or Jack Johnson but you really don't know because they were from different era's with different training procedures, etc.
Every president was a product of his life experiences and environment. Presidents vary from horrible to inept to uplifting to smart to brilliant politicians, etc. But all were politicians in the end.
I can't pick the greatest, so I'll list a few I find to be very impressive. Not in any specific order.
FDR
He won after the worst economic disaster in history
and gave the country hope. His predecessor went fly fishing for 3 years with pictures of him (Hoover) in the paper having fun while people went hungry. FDR strongly supported unions that built a huge middle class tax base, started Social Security so that old people got $40 a month to help them survive, started public works programs to help with unbelievable unemployment. He had flaws, he was a millionaire politician, he was somewhat racist and I'll address that before I'm done.
Lincoln
Probably was president in the worst possible time to be president and kept the country together despite watching over 600,000 people die brutal deaths. Ended slavery and got shot in the head for it. He battled depression before people knew what depression was, but you'd probably be depressed too if the country was literally killing each other in a bloody civil war that you weren't sure would end with the country intact. He also had racist tendencies, but understood the 'greater good' and did the right thing.
Jimmy Carter
Anyone who won the 1976 election was doomed, period. The other party was going to win after that 4 years of economic and foreign political hell. I've often contemplated that if Ford had won, we never would have had Reagan which would have been a good thing. Reagan was the definitive laziest president up to that time and his trickle down bullshit still hasn't trickled down.
Jimmy was the last president to avoid war, had to deal with recession, inflation, Iranian revolution and the hostage crisis and OPEC running oil prices through the roof. A lot of those problems were directly related to this country's support of the crooked, evil Shah of Iran so we could buy gas at 32.9/gallon from WWII into the 1970's. And Jimmy publically supported him like the others and like anybody else would have done at that time to his political demise. He is the most underrated president and he spoke the truth about sacrifice that people didn't want to hear.
JFK
The best speaker of all the president's that were recorded. Inspirational leader with 70% approval at a time when politics still had an element of mutual respect. Pushed for civil rights and become all in on that subject even though he and his brother first thought of it as an annoyance. They thought the cold war was the biggest problem facing mankind and put civil rights on the back burner for a year, but they both evolved rapidly and did the right things in the end. And both got shot by madmen for it. The world would be a different place with different history had they each lived just 10 years longer. I personally don't think we ever recovered from those assassinations with MLK also shot between them.
Barack Obama
The absolute squeakiest clean president in history. They could never dig up dirt on him so right wing conspiracy writers like Jerome Corsi just made shit up. And Fox news and Trump jumped on it and repeated it over and over again until it caught on with the brain dead conspiracy lovers. Not as good a speaker as Kennedy, but a near flawless personality that didn't need to fuck movie stars for fun. He had help following a president who was there when the economy tanked bad and inherited a fucking mess. If you look at any economic graph starting in 2008 through now, you'll see who got those graphs moving up nonstop until present.
He had to deficit spend to avoid another depression. Of course his vile successor didn't have to deficit spend but does anyway at the future expense of the environment and economy. The next correction may be vicious, save your money.
LBJ
Probably the most influential politician in my lifetime. A racist, but one who did the right things with the civil rights act and voting rights act. He may have not particularly liked black people, but he gave them equal rights at least on paper. And he knew full well it was at political cost. He said after the 1964 CRA that he probably lost Texas for the next 20 years. He miscalculated, it's been over 50 years now. Yeah, I know some of it was politically motivated to get black votes but he still did the right thing on many social issues including medicare.
The Gulf of Tonkin and Vietnam were the horrible things he did, much better at domestic policies.
About racism and discrimination of previous presidents:
The country was founded on slavery, you don't have to like it, but you have to acknowledge it. It took a civil war to change that and another 100 years for civil rights on paper, if not totally in reality.
Entering the 21st century there were still problems but it's overall better now than it was in previous centuries albeit far from perfect with much work to be done.
When FDR sent his wife down south to try to stop lynchings, it was because he was politically scared of losing the south he needed to stay in office. All these guys were politicians first, presidents second.
And when he put Japanese Americans in camps during WW II, it is wrong in retrospect. But at the time, there was no outcry from Americans to free those people. The country was scared of Japan after Pearl Harbor, the west coast put up barbed wire on the beaches and had blackouts at night. They were literally worried about a Japanese invasion force after Pearl Harbor.
Racism played a role in Pearl Harbor as well, many military officers thought Asians were 'too stupid' to successfully carry out an attack on an American installation because they were ridiculously racist and thought only white men could wage war and win.
My dad fought in the Pacific in WW II from early 1942 to early 1945 when he had enough points to cycle out. He was a lifelong FDR union Democrat and strongly supported civil rights in the 1960's. But he didn't like Japanese people for years after WW II until he actually met and played golf with several groups of them in Myrtle Beach in the early '80s after he retired. A lot of Japanese vacationers would travel to Myrtle Beach back then. He played and had lunch with people who served on the other side in the Pacific Theater and became enlightened that it was their government, and not them personally, who was responsible for that Pacific war and he died not hating them anymore.
People change, societies evolve, personalities are flawed but surely we're in a better place today that we were in 1969 or 1959 or 1949 or 1939, etc.
That's not to say we're done or that in the last 3 years we haven't been going backwards under Trump.
We'll be rid of him soon. Much like FDR's wife went down south to appeal for sanity against murder, it's the women who will turn the tide against this horrible backward slide in our history. We're one election away from turning that tide. I'm optimistic and will never throw in the towel. There's always hope and the dream will never die.