Imagine that you are having dinner with a vegan family. It's a feast with many friends and extended relatives gathered, all of whom are vegan. The parents were raised vegan by the grandparents. The friends of all the vegan kids are vegan. Everyone at the table has interacted with mostly vegans their entire life. What would it be like to have dinner with those people? How would you react when others casually discuss meat eaters as very bad people? Would you just ignore it? Would you interject to let people know, that actually meat eaters are just people, too. You could lie to varying degrees in ordere to fit in, either by omissions of detail or complete fabrications.
Now let's imagine that one of the people at the table is your best friend. What if it's the woman you want to marry? What if it's your boss? What if it's the owner of the company you work for? Many of these things can change how likely a person is to approach the situation.
For the sake of the example, let's say the person is the love of your life; the woman you want to marry. And also for the sake of the example, so far in your relationship with her, you have not clarified the extent to which you were a carnivore your entire life. Upon meeting her, it was easy to simply assimilate, adjust to her eating habits, and enjoy the type of food she eats. Eating meat isn't really a big deal for you but neither is not eating it if you can enjoy that time with her.
As the relationship develops with time the extent to which you can owe the situation to politeness, having just met, or not getting around to really talking about it yet diminishes. Eventually it comes to a head:
"So... You don't eat meat right? Like ever? Did you ever eat meat before? Do you feel bad about having done that knowing what a terribly wrong way to live it is? You do think it's an objectively wrong way to live, don't you?"
Now I know that many Christians think that atheists have no sense of morality but they do. God wrote natural law onto the hearts of men so they instinctively know it to some degree without needing to have it explained to them. But the sense of morality that atheists have is less uniform than ours. It's not informed by knowing God. But they do have some sense of what is right and wrong, even if they must do gymnastics to explain where it comes from or to ignore it.
So for the sake of this example, let's say that you do not want to lie to the love of your life. Imagine how badly a person could want to believe something and not be able to do it without lying. Imagine that there is a switch above their head and all they have to do is reach out and touch the switch and suddenly they are truly belivers. Imagine that there is a switch above your head that you can switch to change your views about the world: your political opinions, your lifestyle, or any number of other things that the average human experience is that you can't just switch on or off.
And yet people change their opinions and lifestyles all the time. How do they do that? The answer might seem obvious but it doesn't sound appealing to someone who is asking, "Do you believe in God?" What does a freshly hired employee at his new job do when he has no experience and is afraid he will be doing something wrong? What does the alcoholic do when he has not drank for a month and is having a craving to go back? What about the out of shape person who is waking up early to do a morning walk and is passing by chiseled, happy runners that seem to effortlessly do it?
They practice discipline. They push themselves to do it even though they don't feel it hoping to come out on the other side as people that effortlessly do. They fake it until they make it.
"So... Do you believe in God?"
I do.
And so can you.