Happiness is only elusive because we always hope that tomorrow will be better than today. As long as we live no matter what our station is in life there will always be something or another we'd like to have in our lives. A large part of living is striving to have more.
Having said that everyone experiences (moments) or times of happiness no matter where they are in life. Laughter, socializing with friends/family, a good meal, or an orgasm can cause one to feel happy in the moment. However when we think of happiness as a "way of life" very few of us obtain that.
If we're lucky we are content most of the time. Everyone has bad days, death of loved ones, ups and downs in relationships, illness, or financial issues. No one gets everything they want out of life!