Sidewalk hogs. People staring at their phones who can't walk in a straight line, groups/couples who spread out and take up the entire path, bike/scooter riders, you name it. The worst are the people who refuse to practice courteous passing behavior -- you can make eye contact with them from five yards away, but they won't make the effort to step a foot or two to their side of the path to let you pass. People from all age groups are guilty of this. It was already an over-grown pet peeve of mine before the covid situation, but it really grinds my gears now!