The pointlessness of life. The absurdity of trying to grasp some kind of a sense of identity when everything, including you, changes all the time anyway. Why does it bother me so much now? Why does it not bother me sometimes? Is it all just brain chemicals?
Also, I wonder if some people are just biologically tuned to feel a sense of disconnection through their life. What if you spend your whole life trying to find a connection to the world or to someone else, just out of reach? The thought that it is something you can work for seems uplifting, but what if it just is something you will always feel, no matter what? Or is it just a lack of connection with yourself? Or maybe there is no "deep connection" to be felt anyway and that is just something you try to obtain so you would not have to face the absurdity of everything. Why does it embarrass me to write this? Hella existential.