Most everything you come into contact with will influence you to some degree, regardless of your willpower, interest level, or awareness of such influence.
Breakfast, history class, Lil' Wayne (yes, I am frequently and unfortunately subject to having Weezy stuck in my head from time to time), strangers, friends...
Whether we soak them in, resist them, or are simply present, characteristics of our surroundings affect us every second of the day, consciously or unconsciously.
It seems the only two ways of controlling how you're influenced are by directing the influence with a conscious reaction (it is nearly impossible to control what discreetly enters your subconscious), or by simply avoiding or changing the influence in itself (which could be considered a conscious reaction in itself, but I digress).
I've had to figure this out over the years battling lustful and depressive tendencies, as well as for a general attempt at maintaining my overall integrity.
It has been, and most likely will be for the remainder of my life, an ongoing battle to preserve my integrity, to separate from the separation of All That Is and Shall Reign Eternally.
At times the gravitation of giving in causes me to make split-second decisions to close my eyes during certain parts of a movie, cease contact with certain people...
One of my all-time favorite bands, The Killing Tree, is something I have limited myself from listening to almost at all.
At first it relayed an intense amount of sympathy, giving my sadness and misanthropy bit of understanding.
But as I continued to listen and digest the vain anger and musical progressions that wordlessly portrayed my hopelessness, I realized the band to be a force to disassociate myself from.
It's like a near-permanent fasting; (I say "near-permanent" because when describing my favorite style of -core music theirs is an example I give sometimes) the absence of that band strengthens me in my overall positivity and when I remember the times it was in my life I can turn my need for peace over to the Prince of the very essence and feeling.
That band is the reason I limit my musical repertoire to Christian artists (and I use that term in the plainest of sense; "Christian" is not something I would add to a subgenre), positive artists, instrumental artists, and artists that inspire nostalgia or produce a certain musical style I find inspiring.
This choice limits me just as a vegetarian may be limited: socially, I become distanced to a degree, now lacking a major commonality; personally, I find, at times, an unsatisfiable appetite.
This choice empowers me just as a vegetarian may be empowered: socially, I find solace within my moral minority; personally, I am doing the best and right thing.
I strongly encourage a self-evaluation on the effect of everything in your life, it drove me to make one of the greatest and most influential choices within my own life.