Hi folks
Yes, bees have "random" ( To Us) behaviour. I Have certainly no challenge to
anyone having observed and reported anecdotal events. After all what one
has observed I take that for granted as truth. Why should anyone invent
tales for any  reason.
In My experience : Hornets and Wasps (Yellow Jackets ) Have a definite
"SPACE" one should not invade. They are also sensitive to vibrations and
become very defensive.
Bees exhibit such behavior also , but with different values of both. With
them it appears it has to do with race , queen , weather conditions,
temperature, ect.
I have my grassclippings pile adjacent to the hives to keep the weeds
away.The weed eater ( Gas engine) and my riding mower poses no reaction as
well. I am not ware of a reaction by my electric chainsaw and the Gas one.
So, that's another anecdotal tale and I am left scratching my head.
Oh, yes, sometimes I get stung when I hug them too much.
catfish