Biggest Mistake of Your Life. Typically used to express your disapproval of something someone said or did. Also can be used as a strong form of advice.
Person 1: Hey guess what! I just got an email from some guy in Nigeria that said I could inherit millions!!
Person 2: Please tell me you didn't give him your info...
Person 1: Yeah I did why?
Person 2: BMYL

Person 1: Hey I just sold my Subaru for a Honda
Person 2: BMYL
by HolmesCT September 20, 2011
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Used to avoid TOS violations on certain forums, it is a way of getting your point across to a troll.

"Thanks for your opinion. BMYLS"
by Javajabbers May 18, 2008
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