We know that first impressions are valuable. When our brain immediately likes someone we subconsciously tend to filter all subsequent information in a favorable light (aka, the halo effect).
In The Elements of Persuasion, authors Richard Maxwell and Robert Dickman suggest we:
…share something personal, and show the audience that you are talking to them, not simply giving a canned speech or sales pitch. if you think about it, this is exactly what the classic comedy act opening does. The comic strides onstage at the club and says, “Hi, I just got back from LA, and I've got to tell you those freeways are something else. Now, I'm from Brooklyn (something personal)… anyone else from Brooklyn? … “Yeah, Where? … Really I know that neighborhood. Wild Place. So, like i was saying, I'm not at all used to freeways …” By being personal and open to the audience, the comedian makes us think, “hey, I like this guy.” And it works even if we are aware of how carefully planned that interaction is.