As listed by others, the misuse of 'literally' bugs me. Slang is one thing (note 'bugs') but when a word is misused frequently enough it becomes the norm, the accepted word, and that is a pity. The roots and actual meaning of a word are left behind and forgotten.

'Decimated' is another of those words. I think some people use it because they think it means 'devastated'.

Words are tools, true. And tools wear out, true. But you can't beat the right tool for the right job.