* EpilepticTrees: Fans have been known to speculate at length about the S&S/''Series/DoctorWho'' connection. [[WildMassGuessing Are Sapphire and Steel Temporal Intervention Agents]]?
** Fan speculation about the ''other'' Elements, particularly ones that were mentioned only in passing and/or during the title sequence, could fill several chemistry textbooks.
* NightmareFuel: Deservedly has its own [[NightmareFuel/SapphireAndSteel page]].
* ParanoiaFuel: Any sufficiently-large assemblage of old objects can potentially summon an EldritchAbomination to destabilise the universe. Beware of museums... (An alternative interpretation of Assignments One, Three, and Five is that it's old-fashioned ''lifestyles'' or attempts to re-enact the past that cause problems, rather than simply collections, although this is not true of Assignment Four.)
* SpecialEffectsFailure: Too many to list; even the expensive and difficult effects look cheap.
* TheWoobie: Mr Tully in Adventure 2.