Origins
Total allows no exceptions. The word comes from Latin tōtus, meaning 'all, whole, entire' — a completeness that excludes nothing. Medieval Latin formed tōtālis ('of the whole'), and Old French passed it to English in the 14th century.
The word entered through commerce and law, where precision about sums mattered. The total is what remains when every item has been counted, every part included. A subtotal is a partial sum — the total-so-far, with more to come.
In the 20th century, totalitarian entered the language for regimes that demanded total control — every aspect of life brought under the state. The Italian fascists coined totalitario in the 1920s, and English borrowed it almost immediately. The -arian suffix turned an accounting word into a political one.
Later History
American English added another layer. To 'total' a car, from mid-century insurance jargon, means the damage is so complete that the vehicle is a total loss — worth more as scrap than as a repair job. The verb captures the absoluteness of the adjective: not partially damaged, not mostly wrecked, but totally destroyed.
Teetotal, meaning absolute abstinence from alcohol, likely comes from an emphatic doubling — T-total — with the initial letter reinforcing the completeness. It was reportedly coined in an 1833 temperance speech in Preston, Lancashire, by a stammering advocate named Dickie Turner.