Last week the WaPo ran a poll for readers to send in their assessment of the most underrated POTUS.
By all accounts Grant was unassuming, decent and easy to get along with, in almost all situations and conditions, other than on the battlefield, when he did what had to be done, and that was that, no ifs, ands, buts or maybes. Most people liked him, he was someone they liked to spend time with. Lincoln was one of those who enjoyed his company. If their son hadn't been ill, the Grants would have been in that Ford Theater box with the Lincolns.
It would be an interesting project to dig into what began all the exaggerations and outright lies about Grant. It seems to have begun as soon as he came to Washington D.C. as POTUS,. It came as much from those who had been Unionists as much as from the Confederate side. Both Henry James and Gore Vidal, whose Americn Chronicles series took much direction from Adams's writing, particularly his novel of D.C., Democracy, had nothing but venom for Grant -- as someone who didn't belong there, out of his league as well as his depth, who didn't understand how things worked.
In Democracy, whose author was the consumate D.C. insider, already the romantic lead is a Virginian who had a brother die in his arms in the Battle of the Wilderness. So the hostility toward Grant, the determination to belittle him went in partnership with the revisionism of the history and causes of the Civil War, and it was immediate.