Seems like Obama was put on a spot more than other presidents. He could say the right things, act the right way[1]; yet if at any point something negative came (drones, nsa) he would be bashed generously. People expect A+ from him and scream at an A-. The sad part is that Trump is said to have been elected because he was felt like a true person; I understand their sentiment, his mouth seems unfiltered, so he's a true nasty person but people still prefer that to someone that looks like 90% good samaritan.

[1] you can find lots of videos where he would adress antagonistic crowds peacefully and wisely. Lots of times where he showed caring (his behavior toward his wife) and a sane personality (cracking turkey jokes with his daugthers).