This 35 minute video explains, exhaustively and hilariously, the personal development benefits of using silly voices in your internal dialog. To summarize: everyone has an internal dialog that they use to make sense of their experiences, relationships and emotions, we can gain more mastery of our thoughts and actions by substituting silly voices or humorous character archetypes. This is a lot times significantly more effective than 'reframing' or just trying to 'think positively'.
As you can see in the video it's also A LOT of fun! Possibly more importantly it instantly reframes negative thought patterns into humorous, jovial lines of thought that you can laugh at.