Any high end bass that has too much 'bling', gold hardware, metallic finishes, too many stitches and knobs, too may pickups (unless its 'ironic' like the Warwick Bootsy Collins star bass). Wal, Alembic, Fodera, Warwick come to mind. Don't like exotic woods on basses either, they look like pieces of 70s furniture.
At the opposite end of complex basses Fender P bass the black/white pickguards/rose wood fingerboard is a horrible combo IMO. It makes a good bass look cheap. I love P basses otherwise.