There are several reasons to avoid a word or expression:
- It's difficult to pronounce and there's an easier substitute.
- It has a difficult intonation pattern.
- It doesn't have any meaning.
Last week, I recommended that you avoid "various" because of reasons 1 and 3.
"And so on" checks all three boxes.
- "On" is usually mispronounced as オン. That's not correct. It's spelled with an "o," but it's pronounced as アン.
- The intonation pattern is the 1-3-2 pattern that Japanese people struggle with.
- It doesn't mean anything.
Let's use English well (and avoid some unnecessary mistakes)!