I have to date, literally never flipped off, yelled at or otherwise interacted angrily with a driver. I’ve to date also rather polite interactions with most drivers, especially ones that approach me when I’m off my bike.

It helps me to imagine people being grumpy because they wish they too were on a bike like me. I’ve literally had people approach telling me they wish they could ride like I do.

Obviously YMMV though and do what you have to do to survive on the roads wherever you are. I guess I’m just saying the drivers around me aren’t not hostile but I’ve still managed a tenuously pleasant relationship with drivers nonetheless. In fact a lot of them know me and have come to my aid at times.