Fairly common on trains into London and on London Transport. Although virtually all commuters are happy to give up their seat to someone who is showing a bump.
People who must use a signature along the lines of 'sent from my >insert name of mobile< using >insert app/system being used>
Pop up adverts
Middle lane drivers
Liars
People who post something that they know is wrong but think it is fun
I better stop before the next post lists people who...