Proclaiming Your Belief
Telling your parents and family that your beliefs are different from theirs could be the hardest thing to do. The more religious the family is, the higher the chances are that they'll try to talk you out of your atheistic beliefs. They'll try everything in their means to dissuade you and to make you reconsider.
Family and Friends Factor
You need to remember that your choice of being an atheist will be especially difficult for your family. They may even try their hand at guilt tripping you into going to a place of worship and involve priests, clergymen, reverends, and other holy men, to make you reconsider. While others will try to introduce you to new doctrines and religions. Preachers will take it upon themselves to 'bring you to salvation'.
Religious Holidays are Difficult Times
As an atheists, religious holidays may become a little tough to handle, as you may not see eye-to-eye with your family. Friends and colleagues may not understand that you might not believe in god, yet love the ritual of getting together family and loved ones that most festivals or traditions demand. This is also the time when theist will try and convince you about the existence of God.
You may even feel that every topic and discussion eventually veers towards an argument about the consequences of atheism. Chances are that you may often find yourself advocating your atheistic believes, while justifying everything with a logical explanation to the world around you.
I'll Pray For You
After hours of justifying and defending your atheistic beliefs, you may often hear a believer say, "I'll pray for you", "I'll pray for your soul", "don't you want to be in heaven with us?", or "may God bless your soul", etc. Using idioms like 'thank god' or 'oh my god' are all invitations to a long and exhausting explanation that you meant to say those words as idioms, and that you're not taking His name in vain.