Let me clarify for the mentally challenged. Your personal anecdote, although relevant to the topic, is irrelevant to the argument.
Saying "I don't know anyone like that" PROVES NOTHING. Like I already stated.
Hope this helps.

I already told you. You're not very bright, are you?

A short statement of your personal experience with the topic at hand. Ergo: An anecdote.

Your personal anecdote is proof of nothing.

Irrelevant