Turning off auto correction or spell check maybe useful to people who normally type in a different language on their android phone.  It is very annoying when it auto-corrects a word that you don’t want to be auto-corrected.   In HTC One you go to the Settings – Language & Keyboard – HTC Sense Input screen and toggle off .  Then move to Advanced Settings and click off Spell Correction and then Word Prediction.    

Galaxy S4

turn off auto correct