Here's a good example of what made SCTV so good. It's a sketch called "What's My Shoe Size?" from 1978.
This aired on the episode where SCTV was celebrating its (bogus) 30th anniversary. The cast was looking at clips of "old" shows - and this was one of them - an obvious parody of "What's My Line?".
SCTV had one of those rare comedy casts where everybody was great. Watch and laugh.