I think if it is related to me in anyway then it would be for the correct path both the epics guide us to and how we should be in our life. Mahabharat gives us a detailed analysis of right and wrong. Dharam and Adharam. Then, ofcourse there is Gita ji in Mahabharat. That in itself lays the path to how a human life should be.
Ramayan on the other hand also talks about how a human life should be but it also shows the sacrifices human life makes for the happiness of their beloved.
Both teach me whatever I wrote above In that way probably they affect my life. Other than that, ofcourse all the Gods and characters teach us something and I love and adore them all equally!
Coming to the favourite one...hmm...
I think it would be Mahabharat. The reason is just that I find it more interesting and that it has many more aspects. No special reason as such :-)
Lastly, which one I prefer to read if I am in difficult times?
Aaah. I don't read any of the above as such during difficult times. During such times, I am just talking to my God, looking at their photos around in my room, crying infront of them, talking about my sorrows and difficulties and how they have always been with me and thank you for that and I don't need anything else but just their support always in my life and their blessings.
Then, while talking and weeping, I don't know when I doze off.
And that's all...I get sad, trouble and just talk to my God. I don't read anything as such. Probably also listen to the bhajans and Shiv strotram @ that time. And the problem goes away sooner or later :-)