One of the biggest counterarguments to not taking action is that as one individual you won't have an impact. If you don't eat beef, the cow will still be killed. If you don't buy products from a company that treats their employees poorly, they still won't be paid or treated fairly. It is not your problem.

But individuals' decisions have an immense impact on the lives of companies and industries. Several companies have suffered, benefited and transformed because of consumer demands that begin with the individual holding companies accountable. Millennials have challenged the existing industries purposefully and unintentionally, either way making a difference on a national level.

Millennials have drastically different spending habits than their parents or grandparents. Without realizing it, you are most likely part of this transformation in the American economy that has brought down Goliath industries and created new ones. Department stores have fallen victim to a difference in preferences between millennials and older generations. Drive past any mall and JCPenney and Sears will either look completely bleak or be barely holding on. Economists and news outlets have also pointed fingers at young adults for the decline in purchasing of diamonds. The mining giant De Beers has seen a decrease of 29 percent in sales in just one year. These impacts are inadvertent, but they prove how widespread the impact of a change of preferences of one generation can be.

Following the shooting at Stoneman Douglass High School in February, Dicks Sporting Goods made the decision to no longer sell assault rifles and high capacity magazines and to raise the age to purchase to 21. In response to the policies, the store's sales surged 27 percent that quarter. After the surprisingly positive response, other retailers such as Fred Meyer followed.

At the beginning of November, the cosmetics company Covergirl announced it is now cruelty-free. It became the largest cruelty-free cosmetics brand by responding to consumers that have refused to buy products tested on animals. In a survey done of American women, nearly three quarters said it was either "extremely important" or "somewhat important" that their makeup be cruelty-free. This change in values creates a change in behavior and creates an incentive for companies to meet higher moral standards.

Earlier this year, the dairy industry began to make news as it tried to debase dairy-free milk companies due to their growing popularity. They sparked debates and proposed acts about whether milk alternatives should be allowed to call themselves "milk." Why doesn't this same argument doesn't exist about peanut butter? Because milk alternatives are challenging an industry that has only thrived until this past decade. More Americans are seeing cow milk as unethical or unhealthy, and this change began with individual consumers and advocacy.

It isn't realistic to say that anyone can avoid buying anything that does any harm to the world. But every purchase is either an opportunity to voice your support for something or refuse to accept injustice. Choosing something you're passionate about and making your buying behavior reflect that passion becomes a form of activism. Change is slow, but by taking action on what you see as ethical and sharing those beliefs, you produce a bigger movement that forces companies to listen.