Thats the problem. Everyone is right in their own mindset. There are infinite ways to be wrong, but there is only one way to be right.
In engineering and applied mathematics, particularly in instrumentation, there is a technique called 'Kalman Filtering', in which a number of error prone sensors are combined. All sensors generate the error in random direction, but the correct reading is identical, and what the Kalman filter does is to reject the random signals and to take only the common reading which is the best estimate of measured data.
Similarly all people have right and wrong thoughts. And as I said above, there is only one way to be right. Dont try to find what is wrong in others, but try to find the 'common right' in others and compare it with yourself, the wrongs in you and others will automatically be distinguished.
And for the Quran / Hadith interpretation, there are many many things to be considered, the time of revelation of any Ayat, the cause/reason of revelation (Shaan-e-Nazool), the surroundings of that Ayat etc etc. For example some radicalist take a part of any Quranic verse which translates to 'kill kuffar', but they dont see these parameters as when the verse was revealed, why it was revealed, what's in the surrounding of the verse etc.