Atheists Doubt?!

It’s funny how sometimes people seem so confident. I meet a lot of confident Atheists and there is no used arguing with them. They think that they are always right. I think that just planting a seed of doubt in their mind is the best way. Just by presenting the gospel. When I was a kid I used to doubt whether I was saved or not (now I know that I am for certain).Why couldn't Atheists also doubt? I am certain that Atheists also doubt their beliefs and think that there is a possibility that there is a God out there somewhere. They shove that thought down and say there is no God. When they doubt they loose their confidence. So if you can plant a seed of doubt about whether they are right or not then it might get them thinking. I think this is a better approach rather than arguing with them. Arguing never gets anyone anywhere and most Atheists don’t listen to logic anyway. These are just some thoughts I had the other night and I wanted to write them down. Let me know what you think. Am I totally wrong about it?