It's just not my thing. People sitting around riffing and skippledy-bee-boo never impressed me at all.
When I hear a band I like I want to hear the music they perform in the way that I enjoy it.
I know how the guitar solos sound in Welcome to the Jungle, Paradise City, Sweet Child of Mine and November Rain. As much as I respect Slash's ability, I don't want to hear him boodely-boo-beeping up and down the frets and changing that up.
Same with Van Halen. Same with Pink Floyd. Same with Boston. Same with Styx, Journey, Prince, etc. When I go see Snoop, I know the words and the beat. That's what I want to hear, not a bunch of self-indulgent riffing.
Same with The Eagles. When they do Hotel California, I have every piece of the end memorized. Why fuck with it?
What Dave Matthews does is, to me, the absolute height of arrogance. It's HIM having fun doodling around. Fuck him.
It just doesn't reach me.
I agree to some degree. Bands like Phish and Widespread Panic annoy the shit out of me with their endless jamming. They play for so long that it completely changes the song. I'm not a huge fan of instrumentals either, so when you just fucking jam for that long, the song loses its original identity and becomes some impromptu instrumental that is played in the same key as the original song.
That doesn't mean that I don't like jamming or riffing at all. Most guitar solos developed from the guitarist "boodely-boo-beeping" on the guitar, and it just became the version they used on the album when they recorded. And, by their very nature, guitar solos deviate from the chorus and verses of the song so as to provide a different sound, often during a bridge. However, it doesn't do so to such a degree that the song loses its identity and is unrecognizable or unenjoyable.
I'm not a huge fan of Dave Matthews, but I also don't view him like I do Phish and Widespread Panic. As jadennis stated, I'm never left wondering what the fuck song Dave Matthews is playing. The "boodely-boo-beeping" is similar enough (and short enough) that I know it's the same song and can still appreciate the sound of that song.
I view it this way: You like the solo in Welcome to the Jungle and know what to expect from it. You like it because you've heard it before, and thus know it and know that you like it. If you go to a live concert and they decide to change it up, you won't know whether you like it or not until you've heard it. Their live solo could be completely different and twice as long, but you can't state that you don't like it until you've heard it.
That's how I view live music at concerts. The band gets bored with playing the same thing over and over for years, and they want to change it up. Sure, I came to the show because I liked the band and what I know about them. But just as with every new band or new song that comes out, I won't know whether I like it until I've heard it. Hearing something new due to a band changing things up doesn't bother me; it's when they completely fucking lose me in non-stop instrumental shit for 10 minutes that I get bored.