'Put off' essentially refers to 'be turned off by something/someone'. For example, 'I was put off by her high handed approach'. Therefore while referring to turning off something, it is better to use the phrases 'turn off' (more informal) or 'switch off' (more formal).
Some errors may only affect sticklers for perfection in language use, others may merely cause amusement, but yet others can be disastrous, as they can lead to misunderstanding, resulting from miscommunication. Avoiding them can only enhance one's image (whether by reflecting how sound one is or by preventing miscommunication) and so may reflect a cause that one would do well to take up.
Notwithstanding the ones covered, that basically encompass language use, there are many that embody mispronunciation (like 'pain' for 'pen' or 'mate' for 'met'), which though equally disastrous would be more easily overlooked as cultural peculiarities.