He used to be funny and a fantastic actor. Then he sold out and spent the money on booze. Now he's really neither.
But go back and watch some of his old indies, for perspective on how he used to be. Check out Clay Pigeons for dramatic acting and Made for comedy.
In Clay Pigeons he plays a charming, country, southern serial killer whose real personality comes out when he loses his temper. He turned it on and off on a dime. "THAT BITCH GOT ME SO FUCKING PISSED OFF....(calmly) usually I'm really clean about it all." Should have gotten a best supporting actor nod for it.
For comedy, check out Made. It's the unofficial sequel to Swingers. He plays somewhat of a different character though. He's an ironically confident but aloof putz. He's not that dissimilar from Larry David in curb. A lot of quick improv, fixating on minutiae, and interesting ways of observing and phrasing things.
Here was a good scene from that movie:
[YT]CH2fHTriaw0[/YT]
Another reason I used to like watching him was he seemingly had no shame. It's uncomfortable to watch uncomfortable people. Now he's seemingly one of those uncomfortable people. He was cringe-worthy in Delivery Man and in some of his more recent sattuff.
I'm kind of interested to see him in True Detective to find out whether he still at least has some of the dramatic acting ability in him. That's a part with actual substance he was offered and has taken recently.