Confirmation Bias:  The tendency to interpret new evidence as confirmation of one's existing beliefs or theories.

For instance: sitting in a bar - drunk - trying to convince the other drunks that the reason I got fired or beat up or kicked out was because everyone else in the entire world is a total asshole and not because I behaved in a manner that precipitated the firing or beating or kicking.  The other drunks - familiar with these results and eager to justify their own bad behavior - would, to a man, leap to my defense.

I believed something.   I sought out people with similar beliefs.  They confirmed my beliefs.  They co-signed my bullshit, in other words.  The truth was extraneous because I didn't care about the truth.  The truth contradicted my narrative.

So my friends speak plainly to me.  I wouldn't have it any other way.  If I'm acting like a jerk I want to be told that I'm acting like a jerk.  I'll admit that at the start it could be pretty jarring.  I didn't want to hear about my failings.

I speak plainly to my friends.  I stick my nose into their business.  Sometimes they don't appreciate this and they react strongly, but I don't care about that very much.  They're my friends so I feel free to speak plainly.

I don't know what I'm talking about, obviously.