"**Complicated**" is a bit hard to cleanly distinguish from _hard_ and _complex_. More or less, "complicated" overlaps with "complex" almost entirely, but complicated seems to imply some level of _external_ influence in its general use, where as _complex_ is used more often in reference to things internal to the subject at hand.
Something can be inherently complex, which then also makes it complicated. But also something _simple_ (like going to bed on time) also feels so "complicated".
This is purely out of my brain. Probably all wrong.
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# More
## Source
- self
## Related
- [[Simple vs Easy|Complex vs Hard]]