Computers and smart phones that seem to slow down and get clunky over time for no apparent reason as if they have some built in obsolescence
New software and operating systems that move around/change all the commands and controls so you have to relearn all the things you new how to do perfectly well and were perfectly happy with for the tenth time now. Make it faster, more secure, more reliable, keep the operation the same, if they switched the clutch and brake with each new car that came out the press and public would come unglued, but we accept the same like cattle on computers and other automated devices.
Yield signs, it is a really simple concept, but seems like half or more don't get it, on both sides, I have people yield to me when I have the yield sign, and people who have the yield sign and still barrel on through.
Four way stops--this is probably my biggest, a third or so just pull up and always think it is their turn, a third pull up scared to death and think it is never their turn, a third try to go in order, but are so flummoxed about everyone else not that they can't figure out what to do either.