OP, bad company corrupts good moral character.

If you are surrounding yourself with people who have poor ethics, moral standards or are tend to enjoy evil things, then yeah, you'll probably notice your life going down the wrong path. sometimes people are good at pretending to be 'good', but you can always tell by the fruits they produce in life and their own misfortunes. people that seem to constantly be in a 'bad way' are that way for a reason and more than likely they brought it on with poor life choices and decisions. Misery loves company, so its often the case that they try to bring yo down with their sinking ship.
Sometimes you need to take a hard look at the people in your life and decide if what they have to offer is good. Its not easy sometimes, as even family members can be poor influences.