Excluding things contraindicated for safety reasons, I taste everything I eat or cook with plain at least once. Some items that have been pointed out as "you would never eat/taste that plain" on another thread:
I have tasted all of these things plain. It's part of how I know whether it's worth it to pay $30/lb for chocolate or $3/lb, whether the $25 a bottle vanilla is better, or just how salty the fish sauce is. I don't expect these ingredients to taste great on their own or raw, but I find the flavor knowldge of them solo useful. I find I am more aware of subtleties in the finished dish when I have a mental flavor reference of the individual ingredients.
We all recognize that some things just taste better made a certain way, or the wisdom that quality ingredients make for a better product. I think knowing what specific things taste like alone is educational on these points and helps make me a better cook.
There seems to be a conceptual dividing line for tasting things plain that certain foods just do not cross in peoples' minds. Apparently mine is either broken or was deleted at some point.
Do you do this? What is your dividing line, or how do you classify things that you want to taste plain or raw vs. those you wouldn't? Is this based on a fear of the yuck factor, or something else?