Like you said, maybe a little bored.
My buddie does this all the time.
Some to warm the tires.
I do occasionally to wear the sides of the tires as my current rear tire is developing a flat spot from too much straight riding.
Some safety advocates are saying weaving like that when coming towards an intersection will make cage drivers notice you more, and hopefully not turn in front of you.
A single light on a motorcycle makes it hard for oncoming traffic to judge your speed, or even see you.
Two lights spaced out a bit gives better depth perception to oncoming vehicles.
I've been riding motorcycles since 1981, and have seen my share of oncoming traffic turning in front of myself and others I ride with.
I've added two driving lights, and black reflectinve tape (lights up white) on the front and sides of my bike.
Mine on the left in this pic:
