The key is to keep company only with people who uplift you, whose presence calls forth your best.

The people around you quietly set your standards, your mood and your sense of what is normal. Company that draws out your patience, honesty or ambition makes those qualities easier to reach, while company that rewards pettiness makes pettiness feel natural. Keeping only the first kind is rarely possible, and a friend going through a hard time may lift nobody for a while without being bad for you.

Take stock of who you spend the most hours with and how you tend to behave around each. Where a choice exists, give a little more time to the ones in whose presence you like yourself better.