Re: Dramatic Irony
Dramatic Irony often creates suspense.
For example, in Romeo and Juliet the Baz Luhrmann version:
While Romeo prepares to drink the poison, Juliet stirs. Romeo doesn't see this because he's looking up, so we as the audience shout at him to look down because we know she's alive. Dramatic Irony. There is a lot of suspense in the moment as we wait to see if he'll notice her moving.
On the other hand, in I Am Legend:
There's a scene where Will Smith's character searches for his dog. We don't know where his dog is, or what's around the corner, but we know that it's dark and scary. We see blood - is it his dog's blood? We don't know, but we hope not. We wait to see, on the edge of our seat, waiting to find out if the dog is dead. Not Dramatic Irony because we don't know what's around the corner, but plenty of suspense.