Discipline and safety come first, absolutely. However, I also try to refrain from trying to make any horse something he's just not. Yes, if I ask him to move ahead and lead for awhile, such as teaching another horse to cross water, bridge, etc. then that's what I expect. And if I want him to hang back to take pictures, bring along children, whatever, then I expect that too. But there comes a time on every trail ride that I want my horse to enjoy and relax as well. And if that's fitting in where he's comfortable, then I try to fit that in to the time frame as well.
I hope that makes some sense.