11. Get a pet to improve happiness
Coming home to a tail wagging dog after a stressful day can actually lower your cortisol levels. Cortisol is your stress hormone and elevated levels of cortisol can increase risk of depression as well as other mental illnesses that can affect your happiness adversely.
This is not restricted to only dogs, research indicates that interacting with animals in general can reduce cortisol levels and elevate oxytocin, the happiness hormone.