Over all I liked this episode, however, something disappointed me.

When Angela was shocked over seeing Peter with Emma I thought "Yes, finally there is something that happened years ago and Angela met Emma once again. Maybe Emma is involved in some kind of experiment and everything went wrong... etc."

But no... There was nothing special behind her reaction. Just a dream about Emma. I really hoped it would be something really big, another dark secret from Angelas perspective that happened years ago.
I start to wonder if there ever will be anything big in heroes anymore. Doubt it.

That made the first seasons so fantastic. We get to know people with powers, and slowly we find out that people have known this for years, and this organisation got larger for every episode. It isn't that hard to create. Just let some of the characters discover... A cave for example, where really strange things happen. Peter brings Claire and suddely a lot of people gets curious and involved with its mysteries. When it gets as most exciting. Angela reveals that she knows everything about that cave, what it can do, what it has done with people, what they used that cave for, and what went wrong.

I mean, why haven't they created something mysterious... Well a carnival, but it had nothing to do with the characters we know.

i think there has something to do with samuel's power, he was watching a documentation that said that his power would increase folds if it collide with an ability of someone( though it doestnt explain whos) may be its emma's...

I have to agree. The shock seemed too extreme and I was expecting something more. We didn't see Mama Petrelli's version of the dream but if it was like Peter's version then Sylar influencing Emma is kinda creepy but not unfixable. I think there's more to see in the dream since we didn't even see the deaths of the people that she predicted. If Samuel wasn't lying about the cello being sentimentally important to him, it would make me feel slightly sadistically happy to see him find out it's been destroyed. Is that wrong?

Chances are destroying the cello was a pyrrhic victory. Now Emma's less likely to trust Peter and more likely to side with Samuel.

Indeed. A cello is just a cello and can easily be replaced if Samuel want Emma to have one, and as you say it's more likely she joins the carnival. And did peter even know what he saw in that dream? The dream didn't make any sense to me...

No, something bigger would be fun. At least people start to get involved in the same things.

Exactly;That's what I wanna see.