There's one scene in which our main heroine (played by Mackenzie Vega) is taking a shower, the door opens slightly so we know it's the killer. She gets out, finds her phone in her bedroom was moved, she looks at the pictures and finds a few of her in the shower. Does she freak out right away and call 911? Nope. She proceeds to go to the bathroom door and compare, I guess to confirm that was indeed her in those pics.

Edit:
The other scene that stood out was, Vega is home alone (her parents leave without her on a trip), and during a wind/thunderstorm (of course), she looks outside and sees something on top of the car she got in a fender bender earlier. She goes out and discovers its a cake with the word "sorry" on top. Now, later she debates whether its from the creepy driver who mentions a cake following the "accident" or her ex-boyfriend. Why she even had to debate is one thing, it's entirely something else that it didn't go straight into the trash. Nope, she kept it so when her two uninvited friends stop over and one eats a big piece, finds it's poisoned... Shocker. Really, really dumb characters.

Oh, and she mentions the shower pics and the friends, smartly for once, suggest calling 911 but she declines as she didn't want to cause any more problems for her parents. For fuck's sake.

At the end, we get a close-up of the licenses in the Driver's inner car roof and of his last two victims. Thing is, the one at the opening (played by the beautiful Cassidy Freeman; born IRL in 1982) has her date of birth as 2001 making her 14-15 in this movie and issued the license in 2013... when she was 12. Like I said, I hope this was done as a joke. FWIW, the dates for Vega's character checks out, born in 1999, licensed issued in 2015.

Vega's character picking up the cake sitting outside on her car and letting her friends consume it was just eye rolling. You don't know where that cake came from. Why the hell would you even consume a cake from a creepy guy who rear ended you earlier or even your dickhead ex-boyfriend who cheated on you? Same goes with her shower scene and seeing that someone took photos of her on her phone.

that the entire "phone shower pics" aspect was badly handled, to say the least. What real-life human being would react that way? A normal person would have, upon seeing the pics (and the erasure of the accident pics), immediately looked around with fright, wondering who the hell was in the house. Instead, this slow-witted girl lines up the sightline with the bathroom and shower, as if there's any question as to what's going on. That's a dumb, time-wasting drag. Then the script continues to mishandle the issue by having her noncommitally question her friends once they arrive. Let's have a pizza party instead!

The script has Hilary behaving unbelievably throughout, such as when Sage shuts off the power and she, instead of phoning 911 from the safety of her bedroom, picks up the bat and calls out down the darkened hallway. Run-of-the-mill slasher-flick idiocy, sure, but let's try to have some better writing people!
Vega and her wimpy friends also open the door when someone begins pounding on it. Of course, there's no peephole, like most post-1950 front doors have.
When the Driver attacks the three friends in the kitchen, Hilary thoughtlessly abandons her female friend, Rachel, and shepherds the drugged Mario downstairs to the room with the conveniently horroristic drop cloths hanging from the ceiling.
In a ridiculous sequence, Driver stabs Rachel with his specialty "grass shears" switchblade, pushes her across the room and thrusts her out the window, then the takes the time to leave the house, get into his car, and run her over in the driveway. An excessively roundabout way to despatch a victim.
Later, Hilary becomes an Amazon woman (remember the zoom in to her determined face), and the predator becomes the prey for a spell. She stabs Driver deeply in the shoulder (no disabling sign of that injury later) and has the wherewithwal to pour gas onto him. Matches, naturally, don't create fire when needed (Horror Rule #273), but Hilary smashes Driver several times with a tire iron. Other than a small facial scratch, no indication of injury later.
Having beaten Driver to the ground, does Hilary run to neighbouring houses screaming for the cops? Why, no, she creeps over to grab her phone from his pocket, then gets into his car and (I'm not making this up!) presses the cigarette lighter, imploring the lighter to "Come on, come on", hurry up, damn it!
The final idiotic character move is after she has left BDSM-clad Driver a smouldering mass on the driveway (no burns evident later). Once again, no running away for help for addle-pated Hilary. No, let's shuffle indoors and try to call 911 on a phone that doesn't work, while absently looking out the window to see if Driver is still prone on the ground. Next thing you know, he's in her bedroom finishing her off. A well-deserved demise for such a stupid character.