So basically, Superman is afraid of:
- Letting people down.
- Lois Lane getting cancer and dying.
- Becoming Doomsday and possibly killing Batman.
- Having his son Superboy become evil (Miss Martian made a cameo!)
- Being bullied as a kid.
From – Superman Vol. 4 #30
They are currently using that for the Superman and Lois tv show. She has recently been diagnosed with breast cancer.