For me, nothing special, just loved it as a kid, and it caught on since then.
It started with SBS svc 160 in Sembawang.. Albion Vikings and Leyland Victories... and hated those one-door type buses, dunno the brand/make but I think is TATA... rampant in svc 167. Hated the LP1113's on svc 137 too.. engine is so loud that they are scary. And like the single door TATA's, the entrance is behind the front wheels.. Then TIBS came to the rescue with RK176's on 160 and 167. By then the SBS B57's and OF1417's had come in. B57's were on 164, double decks were on 169 before TIBS took the services over.
160 back then went thru Jalan Besar on the northbound trip, before TIBS rerouted it via beach road much much later. And also renumbered it into the present 980.