Can everything which can be used for good also be used for evil?

everything has a good and evil outcome, whether or not its expected. life, love, weapons, everything. take love for instance. if a guy falls in love with a girl and she loves him back, his life will be so much merrier and happier. he would feel good and spread that feeling by being kind, pleasant, and helpful to those around him thus causing good. but if a guy falls in love with a girl, and she treats him like crap and then runs off with another guy, that same love can drive him towards depression leading to low self esteem and self worth, leading to drinking, getting high, violence, all that good stuff. but in either situation, there will always be both good and bad, because nothing is in black and white