We could be wrong about everything. There are very few certainties in life and there are only a few I can think of.
1.) Right now I'm having an experience of some sort. This I know is an irrefutable fact but I do not know what is behind this experience. I could be a spirit as the religious claim, just my brain as scientists say, I could be having a hallucination, this could be a super high tech test from the future, or just anything we can think of. I don't believe in any of the stuff I just listed personally, but it certainly is a possibility if I'm honest about my own knowledge.
2.) The future is uncertain. This is also an irrefutable fact because there are always things that happen that we don't see coming. No one expects to have a car accident on a nice day, no one expects that they will become homeless due to an oncoming natural disaster, no one would expect to have their house broken into. These are things that different people all over the world experience everyday and even though this list is pretty extreme, I believe that we all face unexpected surprises no matter how big or small and good or bad.
3.) I don't think this one is fully and applies to all situations, but I think that while conscious we are mostly in the past or future in our own minds. This is another one that I imagine is true for us. We are either thinking about something good or bad that happened in the past or anticipating something for the future. Even while at school, work, or wherever you can find yourself daydreaming or remembering something. We are always anticipating the future and contemplating the past. We are only in the present temporarily when we have to focus. This is the wonder and horror of human thinking. Animals don't seem to have the ability of having an urgent need to expand their own lifespan or foresee death as it's coming right at them. Most animals seem to just react because danger equals pain but I'm really not sure if they contemplate death or not.
The first 2 things on the list I think are irrefutable. I can't even imagine how I cannot be having an experience nor can I foresee the future. The 3rd one is touching more on how our minds are always constantly stimulating consciously and unconsciously (if you have a mind that functions properly) over things in the past and the coming future while spending very little time in the present.
I brought this subject up because I was thinking about my atheism. I'm not sure if many atheists feel worried over so many uncertainties like myself. I am a person who thinks a lot to myself and find myself always questioning things over and over again. I'm sure plenty of atheists feel comfy because they have a plan and are only bothered by uncertainty when situations get heavy. I don't really have any direction for my life because I don't know what I want to pursue and for what purpose. I really am a question mark in my own eyes and sometimes I just get scared from so much uncertainty that is accompanied with life. I just wanted to rant off about that and I doubt it's all that interesting but at least I feel a bit better.