Where are the confidence intervals and error bars? In order to be taken seriously when aggregating 1.8MM comments, you need those. The variability in pg's plots makes me think the data for any individual is going to be just as noisy.
Anxiety/Confidence PG: p <= 0.0007 HN: p <= 0.0001
Hostility/Compassion PG: p <= 0.0005 HN: p <= 0.0001
Depression/Happiness PG: p <= 0.0067 HN: p <= 0.0001
Note that for the HN comments, even though I used a 2nd order (parabola) fit for the graphs, the p values above are for a linear regression as that is the more appropriate fit for determining statistical significance here.