system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why, despite having a majority on both house and senate, President Obama had such a hard time passing legislation

I know the issue had something to do with the GOP's power, or threat of, fillibuster, but if I am not wrong, the GOP never really used this all that much. Many thanks in advanced for putting this in plain words and providing sources if possible.
gpt
Two main reasons:

1) No party will have a solid 60 person majority; the country is too divided. Even if you have 60 "D" or "R" senators, a decent amount of those are going to be moderates that won't always fall in line with their party. This is because a few of these people will be D's in places that usually elect R's or vice-versa. Thus, they have to show they aren't a shill for their party. 

2) There was only a 60 Dem majority in the Senate for roughly 2 weeks. Remember, it took months for Al Franken to get sworn in (due to the recount), and Ted Kennedy was incapacitated just a little later. Then, Scott Brown (R) was elected to take his seat.


Were there things the Obama Administration could have done differently to pass more stuff? Yes. No one, however, expected the R opposition to be as lock step as it was, particularly in regards to bills that R's themselves were trying to pass just a few months earlier. It was quite literally unprecedented. But as they say, hindsight is 20/20.