I always wondered why Beck seemed to swap between upbeat and folky rock for his albums... here's the explaination from AllMusic.com:

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Beck released his debut album, Mellow Gold, in early 1994. Mellow Gold received rave reviews and became a gold record as "Loser" climbed into the Top Ten. Beck's contract with DGC allowed him to release records that he and the company deemed as uncommercial on indie labels. Consequently, the singer/songwriter released two new records by the summer of 1994, which were both recorded roughly around the same time as Mellow Gold. Stereopathetic Soul Manure was a noisy, more experimental album than his debut and was released on Flipside Records. One Foot in the Grave accentuated his folk roots and was released on K Records. Neither album sold on the level of Mellow Gold, but they sold respectably.

Throughout 1996, word-of-mouth began to spread on Odelay, and earned Album of the Year status from most major critics' polls and, even more surprisingly, it received several Grammy Nominations, including Album of the Year. Originally slated for release on indie label Bong Load, Mutations instead became Odelay's "unofficial" follow-up when it was released on DGC in the autumn of 1998; the soul-influenced Midnite Vultures followed a year later. Beck teamed up with Mutations producer Nigel Godrich again for 2002's wonderfully melancholy, stripped-down Sea Change. That summer and fall, Beck embarked on two tours: one was a solo acoustic jaunt that featured some guest stars, such as the White Stripes' Jack White, the other was a full-band excursion featuring the Flaming Lips as his opening act and backing band.

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