Well, first of all it's not totally clear to me either. It's been coming at me from a few angles which I'll try to mention (Most of my question marks will be of rhetorical nature. I don't necessarily want them answered):
a) Church is so friggin institutionalized and formalized. "No jeans allowed when playing on the worship team." There's many other such man-made rules that don't make any sense to anybody but get upheld because we have to. Why? This just makes people uncomfortable and is pretty pharasaical. There's many other unwritten rules about how to behave and how to not disturb formalisms in church or in the service. There's no room for people be themselves, to share, to open up. Everything caters to masking yourself.
b) We don't like sinners. They're so friggin annoying. It's so vulgar when they're honest. But honestly, we don't know how to face them. Their pain makes us uncomfortable. Oh, and I think we might've forgotten that we're sinners as well and sort of lost (without Christ).
c) Let the little children come to me. Our worship service is so formal that kids are bored and any disruptions from them aren't very welcome. Of course this holds for other participants as well.
d) We're a little judgmental. Now I'm certainly stepping on toes here. No, Christians aren't judgmental. They just try to point out sin. And they try to fix it. Yeah, I know. I always try this to my girlfriend too when she's had a bad day and don't really get why she's pissed at me when I do (note that this is entirely fictional). We don't seem to know how to provide a safe environment for sinners (without endorsing sin). We've sorta missed what pubs and clubs seem to accomplish well.
e) Some of us think that our church is the only good church. No, we won't admit it cause we feel like there's something wrong with it but we won't move to a city that doesn't have a church like ours. And we strongly try to convince people that went to another church to come back. Isn't there something off with this?
f) We've build a wall, a comfortable shelter (or should I say hole) so we don't need to trouble ourselves with the things that make us feel uncomfortable (our own inner being and other people's inner beings).
Disclaimer: I know there's a lot right about church but I'm not trying to get at that. I'm trying to just point out the things that aren't.