When Kakashi uses his MS he feels the hatred of the Uchiha.

[Bansho Tenin]

If you ever notice, he becomes a lot more serious when he's using it. Other than the fact he NEEDS to use it in such situations, or else he would be dead. I'm sure he feels the hatred of the uchiha. As Tobirama said, their brain changes when they activate their sharingan. And Kakashi's MS activated while in his head... so something must of happened to his brain as well.

Just a thought.

 

[Zuru]

Maybe he feels Obito's hatred, since it is his eye after all.

 

[Fodder#5]

It is possible that he experienced some sort of neurological damage as a result of the MS. But I think that his seriousness can be attributed more to the situation at hand. As Uchiha characters have stated previously, Kakashi is not an Uchiha. So he would not be genetically predisposed to the hatred of the Uchiha

 

[Sasukenumberonelover]

Well when he only uses it when the opponent is really strong .. of course he's gonna be serious .. :|

 

[Bansho Tenin]

Well it did activate inside his head at the same time as obito.

But obito awakened his MS when he was crushed. Just the one eye.
the other eye went into Kakashi's head. it wasnt even a 3 tomoe sharingan.
When Rin ran into Kakashi's raikiri on purpose he awoken his MS.
Then both of theirs activated at the same time?
Linked, maybe, probably.. Obito saw images from the eye. He is the owner of that eye.

 

[ShisuiReborn]

Well it did activate inside his head at the same time as obito.

But obito awakened his MS when he was crushed. Just the one eye.
the other eye went into Kakashi's head. it wasnt even a 3 tomoe sharingan.
When Rin ran into Kakashi's raikiri on purpose he awoken his MS.
Then both of theirs activated at the same time?
Linked, maybe, probably.. Obito saw images from the eye. He is the owner of that eye.

I believe Obito got his MS when he saw Rin die. Him and Kakashi activated it at the same time.

EDIT: Here's the chapter I'm thinking of:

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(My laptop doesn't do the whole picture thing..)

 

[Acid Ace]

He's biologically not an Uchiha, so I don't think so.