For me, it’s the determinism of nature. The clear hard fact that nothing I can do will impact the pre-determined outcomes. This is cold physics as we know of to

For me, it’s the determinism of nature. The clear hard fact that nothing I can do will impact the pre-determined outcomes. This is cold physics as we know of today. Also, the ‘present’ feeling different from past is just a trick our mind plays on us. This realisation has had profound impact on me - but this dawned on me quite late despite reading a lot on this topic for years.