No matter how well you know the area that you're speaking about, there always will be someone who is proud to know more and may potentially call you "fool".

No matter how poorly you know that area, there always will be someone who is proud to know even less and may potentially call you "nerd".

If you're afraid of being offended by those two types of people, the best suggestion I have for you is to glue your mouth with duct tape and never say a single meaningful word ever again.
Bullshit detector: when you hear a person talking around a theme of "how great it is to be creative" don't forget to spend fifteen minutes to google out what art has she actually created, just to figure out whether you see an artist or a blabbermouth.
"Being creative" is a sweet undemanding social badge. Creating stuff is an exhaustive work.
When somebody preaches you that "there's no such thing as class warfare," suggest them to go ask for salary raise.
The difference between a wise person and a smartass is that it's charmingly easy to force a smartass into proclaiming lack of systematic education as a virtue.
Sometimes it's possible to pre-calculate the discussion with a free will/free thought afficionado five or ten arguments upfront.