Riding alongside traffic and in congested urban areas.
I love zipping in and out like you say, Serge!
I will say this having wrecked many times, don't break the moneymaker!!! Last year — at probably between 15-18 mph down a bridge ramp I hit FOD and ended up parallel with the ground before crashing and causing many layers of missing tattooed skin (I wasn't wearing a helmet that day..I wanted to look 'cool' as I was already 500+ miles in as a self-proclaimed 'pro' Half Bike rider, lol). I was lucky to have landed with my left arm extended and my head crashing in to my shoulder/outstretched arm instead of the ground...no concussion!
So, if you're not wearing a helmet, you're gambling with your life!!
PS: I've crashed a few more times, since...some by almost getting run over by a left turning car, but bones heal, head trauma...not so much...ride safe everyone!