It's interesting. A lot of the responders here seem to be smoothing their ruffled feathers by invoking various bass virtuoso's such as Wooten, Jaco, Stu Hamn, et al.
While this is all nice and good, I'm not sure that this represents the technical skill level of 95 percent of the bass-playing community.
After playing guitar for 6 years, sometimes up to 8 hours a day (I dropped out of high school and didn't have internet at the time...) learning scads of theory, and having become decent at a plethora of styles ranging from metal, to bluegrass, to Latin It hen picked up bass.
I picked up bass after I had finally got my sh*t together, got a BA and was about to enter law school. As my time dwindled, every time I picked up the guitar I noticed that, due to lack of practice, I was getting progressively worse and this depressed me suh t hat I pretty much stopped picking it up entirely.
At the same time, my musical tastes were progressing into Jazz and Fusion etc. I listened to Bela Fleck and Flectones all the time, as well as weather report, and absolutely fell in love with the bass.
I figured that while I got progressively worse on the guitar, I could only get progressively better at Bass as a beginner.
10 years later I can say this. Technically speaking, playing bass well (not incredible, but well) is easier than guitar. However, laying down a proper bassline requires a lot more creativity, sensitivity, and a good amount of "looking forward."
To illustrate. I play along with songs a sync up on Go Playalong (best thing sincesliced bread) and I can play even fairly difficult songs without too much practice time. However, when I play in a live situation when I have to come up with something interesting and supporting on the fly, with just the right amount of notes, and getting those fills to land just right...Well let's just say that sometimes I want to rip the guitar out of the guitarist's hands and play something with a lot more notes and feel a lot more comfortable with it.