Explain the meme's.

[Stewie7Griffin]

Okay, I don't go to 4chan, so there are a lot of memes that I understand, but I don't understand why people use them or where it started. I, personally, find memes to be highly annoying. If you care to tell me the origin, or reason why it is done, of the following, feel free.

Face palm: I cannot stand seeing people use this as a statement.

Example:
Larry: Phsychology is spelled with an 'S' right?
Joe: No, it's spelled with a 'Phs'.
Larry: But it makes the -insert 's' sound- sound and not the -insert f sound- sound the 'ph' makes.
Joe: Face palm.

In Soviet Russia: This makes no sense.

Something.jpg: I don't get this one. People add .jpg, .bmp, or .avi to the end of random statements.

I just don't understand why people use these. :/

*EDIT* Also, feel free to add others to this list.