What is it that drives the animosity that a lot of bass players seem to harbor toward guitarists, calling them "guitards" and claiming that they somehow can't possibly "get it" about bass? It's petty and it just makes you (if you act this way) look insecure. We're all in it together, folks.
It's because there is a definite philosophical difference between the typical bassist and the typical guitarist. Most bassists are focused on making the band sound better so the song will sound good. GOOD guitarists are as well. But a sadly large portion of the guitarists that many of us have worked with are fully convinced that the band is there just to help people pay attention to THEM.
It even makes sense when you look at how most people start on their instruments. Bassists are generally aimed at accompaniment from the beginning - "Every band need a bass player." Guitarists often learn how to burn off a solo long before they learn to play a backing part.
That's the basis of the different philosophy, right there. We're there to support the band. The guitarists we complain about the ones who are sure that the band is only there to support them.
Mature guitarists, the ones who don't get called 'Guitards', approach ensemble playing more like a bassist. Generally they are also the guitarists who do best playing bass.
A great way to detect for attitude is to ask who they play with: Guitards say 'My band...' Real guitarists say ' This band I'm in...'