What if there is? Changes nothing. It's lazy, incompetent and/or malicious. Epicurus was on point so long ago.

If there was a God he or she can go fuck themselves, period.
First off what kind of God would kill his own kid to prove he loves everyone else if they act like and follow his kid. I want no part of that.

Becuase there is no evidence.

When I say I'm 100% sure, I'm saying I'm 100% certain that there's no physical, verifiable evidence that even remotely suggests the possibility much less proves the existence. If we're really going to say we aren't 100% sure because a little book says otherwise, then you may as well say you're not 100% certain that Superman exists and reversed the rotation of the earth at some point.

if there was I would have killed the motherfuker a long time ago.

The idea of God is a human construct to give people power, comfort, fear, etc. The Christian God is no different than Thor, Athena, and so on. If you embrace the concept of one, might as well embrace them all.
However, there is no incontrovertible evidence to support the claim of the existence of any deity. Hence, I am 100% sure.

Do you believe in Santa Claus?
Do you believe in the Easter Bunny?
Are you 100% sure??
Same thing.

The same way I am 100% sure there is nothing hiding under the bed, waiting to get me. Because there is literally absolutely nothing indicating there is one.

If there is a god, I'm gonna tell him what a fucked up job he/ she/ they/ it is doing

Because that is NO real evidence supporting the myth.

Well, to make the existence of god possible, even with the smallest probability; one must have distended the meaning of the word "god" so much that it won't be different from alien or an extraterrestrial being.
The gods described in various religious texts are so ridiculous that one has to completely close his eyes to logic just to make their existence possible.

I as sure that there is no god as I am sure that 2+2=4. And I will be sure of it until I am presented clear evidence that 2+2 does not equal 4. If that’s 100% then I’m 100% certain there is no god.

It’s for the same reason that I know that Sasquatch is not cooking me dinner tonite: if god existed as billed, I couldn’t harbor any doubts regarding its existence.

Those of you 100% certain there are no purple winged polka dot dragons that orbit the earth. Or, is that reasonably possible? Or is this something that a reasonable human intellect "cannot know".

God can be a mushy topic where you need to define what your definition of god looks like -
is it the 'my person jesus who I talk to and who answers my prayers' then I would say 100% no.
If it is the 'distant judging father figure' version then I would again say 100% no as he would be a pointless uncommunicative bastard.
If it is the 'power of the universe' sort of impersonal amorphous blobby power thing then I would say meh not sure.

Don't care

Whether or not I'm 100% sure or not depends on how "god" is defined. If it's an omnipotent, omnipresent, omniscient, timeless, spaceless entity, then yes I am 100% certain that does not exist because that definition is self contradictory, and at times meaningless. Omnipotence alone is self contradictory. omnipresence makes no sense when combined with timelessness and spacelessness.

There is no proof at all of a supreme being. Humans have made thousands of gods, yet there is no evidence of one. Not a single one. I'll live my life as I see fit and take my chances.

Those of you who are 100% certain of anything but your own existence...
How can you be so sure?

Because it's a baseless idea. ☺

God is a fairytale and nothing more ; where is the proof that he does exist? We have a lot more evidence of evolution just from the fossil records and the layers of limestone.

Nobody asserts that. They assert they have 0% belief in a god, the same way most 'believers' lack any belief in the thousands of gods of other religions.

Perhaps I'm a weaker atheist here. If someone were to ask me if any god(s)/supreme beings exist I say: I don't know, but do not believe they exist because I have seen no compelling evidence to suggest that they do. If they were to ask me if the god(s) of all of the religions known to man exist, I'd say no or highly unlikely. As there is no good evidence or good reason to believe any of those exist, and highly faulty definitions of their own gods. Freewill for one cannot exist if a god is omniscient, that's just one example of how the christian god, as an example, is self-defeating. To add on to that, they all use the same justification for their existence. None have more evidence than another. Not all religions can be right, but they all can be wrong. What does the tell you about the faulty reasoning used for all these gods? If all gods existence (the greek gods and the christian god, as an example) can be proven on the faulty method of faith, then how reliable is faith? Why believe any exist when there is not enough or no evidence, currently, to suggest that they do? I'd say believe something after it has met its burden of proof and not before.

We have to agree on definitions before we can discuss anything. What do you mean by the word god?

You can't be sure but you can't be sure about many things.