One of the main differences between your daily commute and your weekend ride might well be that, in the latter circumstance, you ride with friends. This changes everything about your mindset and the manner of your riding.
Although your 'Sunday blast' with friends might be a big deal, don't treat it as a race, and try to avoid getting too wound-up. We know it's almost inevitable that it will involve machismo, but fight the temptation; if it feels too scary, roll off. You'll get another chance to ride your favorite corner on the way home.
When overtaking, consider the rider following you and give him room to pull in behind. If you're following another motorcycle, don't base your overtaking decisions on those of the rider in front.
When passing cars, the safest bet is to do so one rider at a time, from the front of the group. Don't come tearing through from the rear and risk having another rider pull out in front of you. Stay in formation and give others plenty of space. Don't attempt to predict their actions and manoeuvres.
The wider the stagger, the clearer the view of the road ahead for each rider, and the more time and space everyone has to manoeuvre.
Make it clear to other riders when you're intending to make a manoeuvre. Rule out any uncertainty by making shoulder checks and giving clear signals.