The hard part is differentiating between personal attacks on the president and legitimate disagreement with his policies.
Personally, I believe Obama is like a carnival barker. All talk with no substance. He's a good showman but stumbles badly when taken off his carefully prepared and coached talking points and scripts.
I also disagree with almost all his policies, programs and political stances, but I'm compelled to respect him as our president. I didn't vote for him and don't particularly like the fact that he's the president, but he deserves the respect that comes with the office. You'll never hear me claim "he's not MY president" like the left did for eight years of Bush's presidency.