I think that the idea of absolute truth is a sham. As you discovered, our memories can be unreliable, and we often let our biases influence our own perception of events. I think that we should be honest with ourselves, as much as we can.

When dealing with other people, things get even more complicated. Since communication is imperfect, we often need to use approximations and stories to get our point across.

Is the mug gray or blue? Depends, on the lightning, the angle you are viewing it from, how good your eyes are, your previous experience with colour, and the clarity of the air... So, what colour "is" it?