What is the function of 了 in the sentence 我最怕去西单了? Received this in a text from a Chinese friend. I want to say that "了" here is not part of the verb phrase but instead just an emphatic particle, same as if you said something like "我最怕蜘蛛了"。Then again, that's not something I would ever think to produce, it just sounds more normal that way to me. Does anyone have a more authoritative answer?
In a phrase with this construct:


  可/太/最 + [adjective/adverb/stative verb] + 了


了 serves as a modal article (rather than tense particle) to express emphasis and is optional.

Reference: http://cdmd.cnki.com.cn/Article/CDMD-10475-1012379314.htm