Because I, and others, would rather not suffer through the circlejerks and phishing for "thanks".
I maintain the only form of "thanks" that should reasonably exist on this site is "anti-thanks". You vote posts down instead of up. Do not hide posts that receive negative votes. Track the number of negative votes a user receives. We all start at zero and only go down from there. Incentivize constructive material by discouraging negative material. Negative votes disappear over time. Divide a user's current negative votes by their post count to assess their contribution.
I maintain the only form of "thanks" that should reasonably exist on this site is "anti-thanks". You vote posts down instead of up. Do not hide posts that receive negative votes. Track the number of negative votes a user receives. We all start at zero and only go down from there. Incentivize constructive material by discouraging negative material. Negative votes disappear over time. Divide a user's current negative votes by their post count to assess their contribution.