Despite being a remarkably simple theoretical model, the Higgs mechanism is the only known theory that is connected to some of the most profound mysteries in the modern physics: dark energy, dark matter and missing antimatter. Measurements of the Higgs boson decay may shield lights on those open questions. In this talk, I will present a few selective results from the ATLAS experiment on the Higgs boson decays. Namely the first observation of the Higgs boson decay to a pair of b-quarks, which had eluded us for many years despite it is the most probable Higgs decay channel; novel techniques to search for potential new physics using the hardonically decaying Higgs boson, and a first search for singly produced long-lived neutral particle that may be realized via Higgs portal. The talk will mainly focus on general descriptions of the measurements without too much technical details, so that the content is accessible to non experimental particle physicists.