Davo wrote:
As far as certain skills more mature players train on (being an avid runecrafter myself)
Last time I runecrafted:

*sigh* Most other runecrafters I'd met had been nice.

I do agree that avid summoners tend to be quite reserved and therefore altogether more mature, same with people who train construction and maybe agility. They're the kind of people who tend to keep to themselves.
Farmers easily make top of the list, as you noted. But they're difficult to find... Go to any allotment and there will be 2-3 people standing there alching, waiting for their crops to grow. Anyone who has any idea what they're actually doing will just whip straight in and out.