The call-backs in Fisk are crazy.
They aren't even required for enjoying the jokes but it's such a tight continuity for a sitcom and it makes rewatching so fun.
Cabbage woman coming back for mediation. Anne, -the library riot woman- wrecking Blendology, and forging her grandmother's will. Debbie Lim can't click her fingers so two series later she has an assistant who will click for her. The phone call where Tony crashes into a bollard followed by that being the reason he has to retake his driving test. Petro's company at the community hub.
And my favourite: Helen telling Ray she likes close-up magic and then successfully doing a card trick for Roz during her pitch.