Much. Helped me develop great public speaking abilities. Also, whatever the reason, helped me to abstain from smoking, drug use and alcohol abuse, or disfiguring/mutilating myself with tattoos/piercings.
Everytime I watch those smoke quitting or drug rehab commercials it is impossible to deny the positive effect that the WTBTS people clean.
Add to that conflict resolution in marriage and other social interactions.
A very inconvenient truth for this forum obviously. No situation is all bad.