A customer wants a battery for his newly bought bait launcher; the original battery is dead. The shop owner digs out a similar cell — “not sure it’ll work” — and builds a pack on the spot: insulate as well as possible, wrap another layer of heat-shrink, then one size bigger, safety first; the heat-shrink is a bit large but works; plugged back into the launcher, switch on, works, “that’s it”, call it ¥50. After that: the customer’s drill isn’t working because the bit is too worn to grip; an angle grinder opened up with not a single bearing ball left and the grease dried solid; a pile of tools for repair, one by one: gears to one side, seals to one side, no power to one side, screws all gone to one side, impact jammed to one side, nothing wrong to one side; when fixing an angle grinder the wheel can shatter all over you, wear goggles; quotes ¥25/20/10/15, “jackpot”; eat the fan’s food first; swap the customer’s ratchet chuck for ¥15, the drill is a write-off. 33k comments: top comment “the boss as customers see him”, 480k; four 18650s plus a board and labor for only ¥50, make me two; is ¥15 for a ratchet chuck even enough for the part; the factory battery may not be as good as the one you made.