i never shy away from a song because the bass line is tough. they're professionals, way beyond my level so there will be things I just cant do at the moment. I just try to figure out the direction of the song and make it work. When I get better I often revisit songs and relearn them, picking up more and more of the stuff i couldnt do.
What I DO stay away from:
1. Any song by Richard Smallwood.
His songs have like 6000 chord changes before it repeats. Its so HARD to commit to memory.
2. Old back in the day songs (like 80's/90's) that's hard to get a clean copy.
Thank God for youtube though. I used to could never find the song only to get handed a CD that sounded like someone taped (yes, cassette) the song off an AM station on the radio while driving through an underground tunnel and then somehow put it on CD. Terrible!!
3. Anything I have to learn off youtube because the artist hasnt put out the song on single/album yet
Almost always a video of them doing it live that somebody recorded on their phone or crappy camera, so the sound quality is crappy at best, all while talking through almost the whole thing. OR its from someone in the musicians area where everyone goes "OHHHHHH!!!!" everytime something happens.
Learning songs like this are a total nightmare for me.