Natalia constanly gets in the middle of gunfights with no sense of self preservation, almost always leading to a game over.

Navi is such an irritation to the pacing of the game, telling you stuff you already know and not telling you info that you desperately need.

Maria, much like Natalia, doesn't move out of the way of incoming attacks from you or enemies, leading to several game overs.

The resistance soldiers have led to many frustrations in traversal, where they'd not follow me and help lead me to where I need to go or by blocking me out of where I know I need to go. They don't stick around for long and you don't require them so not as bad as others but still annoying.
Alyx & Barney can have their moments, but they have much more health and are single people compared to a platoon of people body-blocking.

While not as egregious as Silent Hill 2, since she hides behind you while you're aiming, but there are still some times where you'll get a game over from Ashley's incompetence making her unreachable before you can save her or she'll not move the one time you have a clear shot. She's also notoriously whiny so add that to the pile of irritation

Sheva's (or whichever partner you have) is notoriously bad at staying alive or having tactical thinking, getting bulldozed away from you and leading to a game over.

Much like Navi, Fi also is annoying, bland and intrusive, but the game suffers less pacing wise and redeems her character by the end so its not all terrible