Most annoying thing in the world? People who refuse to admit obvious things like "Yes, women avoid you because you're fat. You can give up on trying to date until your BMI is within the acceptable range, which is between X and Y. Also, why haven't you had bariatric surgery yet? You know that lifestyle change only works for 1 in 100 people, right?"
All my friends were polite and full of platitudes, and I had to slowly figure all of this out on my own. They could've just told me at age 20.