Guilt

The Teller's telepathy allowed it to detect guilt. (TV: Time Heist)

Bennett killed the survivors of the crash of the UK-201 to conceal his guilt. (TV: The Rescue)

The Valeyard attempted to prove the Sixth Doctor's guilt during the latter's trial. (TV: The Mysterious Planet, Mindwarp, The Ultimate Foe)

C'rizz felt guilty for killing L'da, as he was unsure as to whether he acted in compassion or panic. (AUDIO: Faith Stealer)

The Eleventh Doctor felt guilty for his effect on the lives of Rose Tyler, Martha Jones and Donna Noble. (TV: Let's Kill Hitler)

The Eleventh Doctor thought that empathics were some of the nicest and loneliest people that one could meet due to their exposure to the guilt, sorrow and pain of others. (TV: Hide)