Incorporate Alan Kay's maxim into 'Prefer simple solutions'. (#306)

* Incorporate Alan Kay's maxim into 'Prefer simple solutions'.

* Update index.bs

as discussed today in teleconf

Co-authored-by: Lea Verou <[email protected]>

* Update index.bs

Co-authored-by: Lea Verou <[email protected]>

* Update index.bs

Co-authored-by: Peter Linss <[email protected]>

* Update index.bs

* Update index.bs

Co-authored-by: Daniel Appelquist <[email protected]>

Co-authored-by: Daniel Appelquist <[email protected]>
Co-authored-by: Lea Verou <[email protected]>
Co-authored-by: Peter Linss <[email protected]>

Author: 4 people

index.bs

@@ -277,11 +277,28 @@ although they may be harder to find.
 Simpler features are easier for user agents to implement and test,
 more likely to be interoperable,
 and easier for authors to understand.
+It is especially important to design your feature so that 
+the most common use cases are easy to accomplish.
 
 Make sure that your <a href="#priority-of-constituencies">user needs</a>
 are well-defined.
 This allows you to avoid scope creep,
 and make sure that your API does actually meet the needs of all users.
+Of course,
+complex or rare use cases are also worth solving,
+though their solutions may be more complicated to use.
+As Alan Kay said,
+"simple things should be simple, complex things should be possible."
+
+Do note however that while common cases are often simple,
+commonality and complexity are not always correlated.
+
+<div class=example>
+Sanitizing HTML to prevent XSS attacks is a complex process
+that requires extensive security knowledge,
+however the [Sanitizer API](https://wicg.github.io/sanitizer-api/) provides a shortcut for this common use case. 
+It also permits simpler types of filtering, but with more configuration.
+</div>
 
 See also: