To "see red," meaning to be very angry, comes from a misunderstanding of what the bull sees in the bull ring. The truth is that the color of the matador's cape doesn't upset the bull at all. Like most mammals, bulls are colorblind. But the flapping and waving of the matador's red cape does tend to irritate the bull, so he charges it. Today, something that provokes one to irrational anger is said to make one "see red."
Chasing a red herring
If anything smells stronger than a herring, it's a red one - that is, one that's been smoked. In Old England, hunters dragged red herrings across a fox's trail to test their hounds. The herring's strong odor would divert many dogs to a false trail. The most talented pups would dismiss the herring as a false clue and advance to real chases. Clever 17th-century crooks would try to confuse pursuing bloodhounds by dragging the fish behind them to destroy their scent.
Tangled in red tape
In the 1700s, before modern filing systems were developed, British civil servants gathered related documents in bundles and tied them together before placing them in cubbyholes. The bureaucrats used red ribbon, called "tape" (though it was not adhesive), to bind the papers. By the 19th century, this distinctive "red tape" became symbolic of the government's exasperating sluggishness. Charles Dickens and Thomas Carlyle helped to popularize the expression.
Red Square, Moscow
The area adjoining the Kremlin is not named for the Communist Party. Red Square was named long before the Russian Revolution of 1917. Its name may have come from the color of the buildings in the area, or the fact that in Old Russian the word for "red" also meant "beautiful."