Very good post Jadecritic2004.
Most of the time I am soloing and not looking for a group but I get at least a couple of invites every night. Most of the time I turn down invites. But when I feel that I have gained good xp I will accept invites.
Groups give me a change of pace and distraction from the boring solo play.
Being the team leader can be very annoying/difficult/draining at times. I never start to build up teams but do very often end up with the star. As you already stated psychology is a very important part of being a team leader. The age consistency of your group ranges from teens to people that are in their 40's, so it is not easy to approach everyone in a way that suits him/her best.
Communication is an important tool of being a team leader as well. But you pick the missions, you choose the strategy, you set the pace and most important you try to keep order if things get messy, after all that is why you have the star and not anybody else. A team that is arguing for minutes because they faceplanted is neither productive nor does it help with getting rid of the debt. To know when to listen to your team-mates and when not is important too. And never stop giving advice to new players, this can have a huge impact on their future style of playing and overall opinion about you and the game.