affair, matter, business, to serve, accident, incident
亊 centers on a concrete matter or affair that requires attention: a piece of business, an incident, or something one serves or handles. The meanings range from abstract 'matter' to specific 'accident' or 'incident', all tied to things that happen or need doing.
亊 is a variant form of 事, which historically depicted a hand holding a writing brush or a tool, associated with recording affairs or serving. The exact development is uncertain, but the character is closely tied to the concept of matters and service.
The shape resembles a hand holding a tool or brush over a surface, as if recording an affair or handling a matter. Think of it as the tool that deals with business and incidents.
For ジ, imagine a busy office worker handling an affair while drinking a cup of tea: tea -> ジ (as in the Japanese word for tea, お茶/おちゃ, where ちゃ sounds close to ジ in this context, but more directly, think of the English word 'gee' as in 'Gee, that's a lot of business!' to cue ジ).