Such as "I am no good." Or "No one likes me." Or worse.
Even if you don't, here's an NPR podcast that delves into the secret history of thoughts while giving us two real stories that begin in pretty dark fashion. Both, however (especially the second one), end on such a joyous note you will get a kick out of listening to them.
Of course, ultimately, this is a great piece of (audio) journalism.
To listen to "The Secret History of Thoughts" on the "Invisibilia" podcast, click here and scroll down to the episode. If you want to download it, click on the "ellipsis button" and choose "Download". You can also subscribe to "Invisibilia" on the Podcast Addict app, which is my favourite app for listening to podcasts while I'm driving to and from work.
ADDITIONAL READING (AND LISTENING)