Most favorite and least favorite are both commonly used by native speakers. The way favorite and unique are used by people who have better things to do than worry about the minutiae of grammar is closer to a hyperbole than a logical statement about something.
The Motley Fool on MSN: The 3 things retirees worry about most and how to address them
The 3 things retirees worry about most and how to address them
Yahoo: Women reveal the things they worry about most when navigating music festivals
Women reveal the things they worry about most when navigating music festivals
Worry is one of the most common reasons people walk into my therapy office. It's usually not a specific worry — it's more of a constant worry about almost everything. And it often gets in the way of ...
I've recently come across a novel called A most wanted man, after which being curious I found a TV episode called A most unusual camera. Could someone shed some light on how to use "a most" and wh...
superlative degree - How/when does one use "a most"? - English Language ...
Most is what is called a determiner. A determiner is "a word, such as a number, article, personal pronoun, that determines (limits) the meaning of a noun phrase." Some determiners can only be used with either a countable noun or an uncountable noun, while others, like most, can be used with both countable and uncountable nouns. Uncountable nouns usually take a singular verb. So, in your ...