To be honest, at the start of the play I was a bit confused as to what was going on. The somewhat dated jargon threw me off and made it hard for me to follow the plot. But as the play went on, I began to understand also appreciate the play for what it was: a subtle social commentary.
"Trifles", the work and the title, presents a sort of irony. Throughout the play, the men always see the women as troubling over insignificant matters like "quilting as opposed to knotting" or "preserves" while they have taken on the important task of solving a murder. At one point on the male characters says, "Women are used to worrying over trifles." But in fact, it's the women who are the ones that have actually solved the case while looking into "trivial" matters. This is where the irony lies.
I believe the Susan Glaspell is trying to relay an important message: Do not overlook women. Do not underestimate women. While the men laugh and roll their eyes at the women, the joke is really on them. While they are going inside and outside and upstairs downstairs trying to solve the crime, the women have already done it themselves. The jagged sewing and obviously the snapped bird's neck are both clues. Women in society are often dismissed as being silly mindless beings, but Glaspell shows us that that's a false characterization.