First, the most credible evidence shows that Obama was born in Kenya, which makes him constitutionally ineligible to be President.
Second, he is actively socializing the auto, banking, and health care industries.
Third, he is actively requiring government approval of salaries in private companies.
Fourth, he is actively spending (or "earmarking" spending for) trillions of dollars which the U.S. does NOT have, thereby placing two or three generations of U.S. citizens in serious tax liability.
Fifth, he is actively fomenting economic policies (e.g., "Cap and Trade") which will raise prices, destroy what is left of the U.S. economy, and push the U.S. into a fourth-world status.
Sixth, he is actively promoting legislation to redistribute wealth in the U.S., thereby creating a socialist (or "Statist") country.
I could go on, but the above more than satisfies your "Why all the complaining about our President?" request.