*All quotes are taken from the Norton Shakespeare, based on the Oxford Edition.
In Act I, Scene 2, Queen Gertrude and King Claudius have announced their marriage; then they attempt to convince Hamlet to stop grieving over the death of his father.
Queen Gertrude explains that death is a part of life, to which Hamlet agrees; however, Queen Gertrude still does not understand why Hamlet is taking the death so personally if he knows that death is a part of life ("...Why seems it so particular with thee?").
Hamlet explains that it does not "seem" to be personal--it is personal. It is not just the black he wears or his desperate sighs, he is truly grieving ("These indeed 'seem',/For they are actions that a man might play...").