Complainers are people who sound bitter about their relative unhappiness compared to their overly-inflated expectations. Faced with new expenses because of a fortunate big purchase, they complain about their newfound "poverty." Faced with their high taxes due to their high income, they complain that they're being mistreated. OK, I grant them the right to let off a little steam. However, wouldn't it nice be they just could focus on their profound embarrassment of riches?
Complainers about such small issues usually can't be satisfied easily because they are forever trying to make up for losses of their earlier life, such as poverty in childhood or loss of a relationship. Or, they may miss their old life or old looks. Take the 60-something woman distressed by her wrinkles and yearning for her 40-year old beauty, instead of appreciating her health or decent looks for her age. Self-esteem plays a role. The better someone feels about himself, the less he complains about his present circumstances. If she feels like a loser, she experiences her circumstances as a sign of failure, anyway, even if they're really OK in the eyes of the average viewer. Nothing is ever enough because what is lacking is inside the soul.
So, what to do? Spirituality/religion answers some people's quest and satisfies them. So can love. Giving to another less fortunate as a volunteer or professionally leads to a better perspective. The man who complains about his new expenses needs to observe people who are really down and out. The lady with the wrinkles should help someone who looks bad because of illness. "I cried because I had no shoes, until I saw a man who had no feet." That old saw really works. Try it when you want to complain.