(No offense intended, although I'm sure some will be taken. This isn't meant to belittle your beliefs au the power of your prayers, it's meant to onyesha why your prayers may offend people)
I am an Atheist. Most of wewe know that. wewe know that I wander around on the Christianity spot so that I can try and understand God and Christianity, even if I don't believe in it. Does my mere presence offend some people here? Does it offend anyone here that I don't like being prayed for?
Try to think about this reasonably. I'm assuming that wewe don't believe in Allah, the Muslim God. Imagine that wewe sat down to chat with a Muslim person, and he realised wewe believed in the Christian God. Suddenly he gets very quiet and says, "I'll pray to Allah for your soul,"
How does that make wewe feel? It makes ME feel as though the person offering a prayer has absolute disregard for my personal choices and beliefs. It's like he's offering something wewe don't want so that wewe can be saved from something wewe don't want to be saved from.
I understand that you're supposed to pray for those in need. I understand that it's part of how Christians help people, but Atheists aren't in need and we don't need help. wewe telling us that you'll pray for us is like me walking up to wewe and saying "I know wewe believe in God, but I'm going to go tell EVERYONE that God doesn't exist, on your behalf!"
"No! God exists! wewe can't go around telling people he doesn't exist, on MY behalf!"
"Hey, I don't believe in God, please don't go talking to the air about saving my soul, on my behalf. It's insulting."
I'm not a bad person, I try my best to be a good person, just like wewe do. I volunteer for charities, I go carolling at seniors' homes in winter, I work in supu kitchens, why do wewe think I need your prayers? Surely homeless people and people who are addicted to drugs deserve them more?
Please don't waste your prayers on a proud and happy person who just happens to be an Atheist.