Generally speaking, rent seeking behavior is always socially wasteful. Attempting to generate income without producing any wealth at any decently large scale takes wealth out of an economic system, and leads to dead weight loss when it occurs in a monopolistic setting. Additionally, certain rent seeking behaviors can cause drains in less obvious ways. For example, patent trolls (holding companies that exist solely to acquire patents and sue smaller companies over patent infringement on those patents) can wipe out innovative smaller businesses that are unaware of the existence of a patent they may or may not be infringing on.