I feel there are 2 considerations, one is for other road users and the second is for themselves.
Round here there are a couple of smaller back roads used heavily by cyclists in particular, though the points apply to runners/walkers equally.
Most cyclists are considerate, but there are some who are not. They ride abreast and make a point of holding up motorised traffic .... because they can. They would be the first to get angry if a car was to pull in front of them and slow down to a crawl, holding them up. Just be considerate (like most are).
The main gripe I have is the apparent total lack of awareness of their environment and their place in it. So many wear black/green/blue lycra and ride on country roads with trees and hedges which make them all but invisible especially when the sun is bright and they are in shadows. I have seen (just) cyclists wearing camouflage. What part of their own safety don't they understand? Just wear something bright and visible, pink, orange, white, yellow etc, something which doesn't blend into the background. Give car drivers a fighting chance to notice them.
Runners (back on topic) generally seem very much more considerate and aware than cyclists, no issue with them.