Choices with whom he associates (that a rather colorful list of characters - and your associations do in fact define you), the choices of churches he attended (again 'colorful' to say the least), and choices that he's made while in office, such as ridiculous legislative priorities (ObamaCare over economic recovery promoting legislation - in fact recovery hampering legislation and regulation).
No, America isn't perfect. But I betcha that it's a dam sight more perfect than most other nations in the world, and yet, Obama's choice, his promise to “fundamentally change America”, when really, America's foundation is probably in better shape than the rest of it, and really not in any real need for 'fundamental change', at least not in the direction that Obama desires.
The opposition party, realizing this, yes, has done their due diligence and done what opposing parties have done since the beginning of political parties, oppose those things which they see as least in the best interests of the nation and it's people. So what's your problem with that? That the opposition party doesn't prostrate themselves before Obama? For Christ's sake, Obama had it all for the first 2 years and could have gotten everything that he wanted in that time, and all he was able to manage was ObamaCare. That should tell you something about his meager capabilities.