Re: Middle finger
Meh... Slower car probably has no clue the faster car wants to overtake there. Then faster car flips off slower car for coming down on him (slower car obvious oblivious). Slower car keep pedaling it and initially faster car gets flustered a little and loses some pace. Eventually faster car gets back on pace and makes the pass, and slower car tries to keep up and actually goofs. Trying too hard?
Not to be a "not there, don't know what I'm talking about guy", but I suspect slower car is driving over his head a little and really doesn't understand circumstance and makes a mistake. Not sure it was malicious.
Finger waving probably a reasonable "sign"... I probably would've done the two hand up "wtf?"...