The three poisons are the root of all suffering. Every bit of suffering can somehow be broken down to one or more of these: greed, anger, and ignorance. Each of these poisons has an antidote.
To reduce suffering in your life, you must apply as much of the three antidotes, as you can as often as you can. It may be easy to entertain the thought that it is the greed, anger, and ignorance of others that are causing your suffering, and that may be true in some cases. But you cannot control that. The only thing you can control is you. Worrying about that which you cannot control will only cause more suffering, so let’s get back to you.