Meaning
What does Trust Nobody, Not Even Yourself mean?
Trust nobody, not even yourself refers to an exploitable image of a photoshopped image of a teenage boy aiming a gun at himself.
The expression turned into a proper catchphrase online and is often cited by users of all sites.
Origin
What's the origin of Trust Nobody, Not Even Yourself?
The image was uploaded to Twitter by user @MohamedKamoul on June 8th, 2014.
The tweet was subsequently removed from Twitter, but the image and the quote still turned out viral.
Spread & Usage
How did Trust Nobody, Not Even Yourself spread?
Screenshots of the tweet would appear on sites like Twitter, Tumblr, Imgur and FunnyJunk.
In December, 2014, a photoshop request thread was created on 4chan, where users would create a large amount of photoshop remakes of the original image.
While the thread was taken down later, many of the edits would survive on the r/4chan subreddit.

External resources
- Know Your Meme โ Trust Nobody, Not Even Yourself