As different as Democrats and Republicans are these days (the average difference about a given political issue is about 35% different between the two... compared to about 15% different in the 90's), the reasons we have two prominent political parties remains the same.
Each party agrees with the policy of ideas of their respective group and are afraid of the other party's polices.
Pew Research explored this topic and revealed the following...
For those who ID as Democrats, here's why:
94% say policy of their party
84% say GOP policies are harmful to the country
81% say they have a lot in common with other Democrats
59% say they've always been a Democrat
66% say they don't have much in common with Republicans
For those who ID as Republicans:
96% say policy of their party
88% say DEM policies are harmful to the country
76% say they have a lot in common with other Republicans
67% say they don't have much in common with Democrats
44% say they've always been a Republican
It's pretty clear as to why finding common ground and compromising, outside of a government spending bill, is almost a thing of the past.
It's clear that whatever your party of choice may be - you likely have very strong feelings about your party's stances and stand in strong opposition to the opposing party's views. The only real difference is where we started politically.
Most Democrats say they've always been Democrats, but most Republicans haven't always been Republicans or don't view it as being important.
Maybe that's the Trump factor?
Regardless, if you're looking for less partisanship and more corporation - it's not in the offing. Technically partisan politicians are representing the views of those in their ranks. Policy is the most important reason for one's political association and it would be hard for feelings about it to be any stronger.