I just tested myself to see how many US presidents I could name, and how close to the right order I got.
I got 34/42(*). Now I can excuse myself for forgetting Franklin Pierce and James Buchanan but how could I forget that Taft comes between Roosevelt and Wilson, or forget Rutherford B. Hayes? ("Winner" of the disputed election of 1876: it had to be decided by Congress, and a dodgy deal gave it to Hayes over Samuel Tilden.)
Yet I remember Zachary Taylor, who died less than 18 months into his presidency. (Shortest is William Henry Harrison, who caught cold at his inauguration, and died a month later.)
More importantly I have the mp3 of the Animaniacs singing the names of all the presidents!
(* - George W. Bush is the 43rd president. This is because Grover Cleveland was both 22nd and 24th.)