I think my issue may be I have a poor understanding of Risk. When I think of risk, I think of volatility.
When I think of risk, I think of the probability of permanent capital loss. I think volatility is a useless measure of long term risk because I don't care if stock prices decrease, as long as the underlying earnings of companies are okay and increasing. Risk to me means companies that have focused production facilities, where one natural disaster can wipe it out, or carrying too much debt, as one credit crunch can result in the company ceasing to operate, or paying too much for a dollar of earnings, which results in capital loss down the road if the company does not grow its earnings in line with investor expectations. These are the things that have me worried about my investments, not if the stock price goes up or down
To OP - it's more of a mental exercise than anything else - do you see yourself clicking the sell button if you see red on your accounts? How do you feel when you gamble in a casino? Do you have extreme highs and uncomfortable lows? The larger the gap between the two state of minds, the lower your risk tolerance is. Investing requires a very specific temperament, and the less tolerance you have for price fluctuation, the more you should tilt towards fixed income investments (or REI, since no one will be quoting you a price every day)
