Why are needles pushed in so far in movies?

This is pure speculation, but I can think of two reasons.

1. Actors aren't medical professionals, and neither are most of the staff on a movie. Most people working on a movie probably haven't handled needles much in their personal lives.

2. They're prop syringes, where the "needle" is blunt and pushes into the syringe. If they don't go into the skin deep enough, you might still be able to see the tip of the prop. The image you posted is actually on this amazon page for a prop syringe.

Because people don't go to movies to watch real-life subtlety. We have real life to watch for that (unfortunately).

Movies are all about blowing subtlety out the door, off of buildings, over cliffs, into CIA mainframes, through time, and across galaxies far, far away, ...and farther.

I don't think anyone was complaining about the medically inaccurate, non-subtlety of this scene:

I'm not sure if the scene would have had the same mythic effect if Vincent had first researched proper procedure on WebMD.com, changed into scrubs, disinfected himself and all surfaces with iodine, and then somewhat timidly went about the procedure with a bit of understandably trepid hesitation.

How computer hacking looks in movies:

How computer hacking looks in real life:

(Irony: the "real life hacking" image is actually from a movie, The Matrix Reloaded, which is revered in tech (or "hacker") circles as one of the most accurate portrayals of computer hacking in cinema. Inception-level irony: the "movie-hacking" image has "matrix code hacking" happening inside it. ...Whoa.)

Video comparison of movie-life vs real-life:

Finally, besides this being a more visually punchy, memorable display of a needle injecting, there's also some practicality involved with the prop: the prop needle is able to retract into the syringe to give the appearance of an actual injection. But most people aren't going to know the real life bounds of needle depth accuracy required anyway, except for perhaps medical professionals who deal with such in real life.

(Seeing any sort of flashy hacking/programming in movies is like nails-on-chalkboard to my eyes, though I understand why)

Why are needles pushed in so far in movies?

They aren't. If the needle had actually penetrated the skin, the skin wouldn't have the depression shown in the question's photo.

It's a prop with a spring inside that provides enough force to depress the skin while allowing the needle to retract into the syringe.

There are two common kinds of injections:

• intravenous — the injection goes directly into a vein and immediately into the circulatory system. This is typically into a surface vein, such as the inside of the elbow.
• intramuscular — the injection goes deep into a muscle, from where it will slowly enter the circulatory system. This is typically into a large muscle such as the upper arm or buttocks.

The photo in the question shows a deep muscular injection into a vein site, which is perhaps why it looked so wrong to the OP. In real life that would be very painful and possibly ineffective. It's also obviously faked, because if the needle had penetrated the skin, the depression shown in the photo wouldn't be there.

Except in those rare occasions where it is used to increase tension and suspense, taking the time to show all the steps in a properly administered intravenous injection would take far too long.

Audiences expect rapidly changing action, so the film industry has developed this meme for a quick injection into the inner elbow. Yes, it's wrong. Yes it looks wrong, even to most of the actors and crew. But that's how it's done in the movies.

It is similar to how mobile phones are disabled by breaking them into two, how concealed bombs and microphones have flashing red lights on them, and how pulling a fire alarm activates the sprinklers. It's all nonsense, but it's a lot simpler and more obvious than reality, and it's what we are used to seeing.