Becoming too focused on the past or future and therefore losing the ability to recognise the present moment. Usually I do this by allowing myself to become my thoughts/feelings rather than just acknowledging them and letting them go. This usually manifests as anxiety or depression and can be really tough to shake! But having awareness about my thoughts helps bring me back to the present moment and helps reestablish the connection to myself - the consciousness/life force that is aware of my thoughts is the true me.