This is no laughing matter: Good composers go out of their way to obscure the difference between a real rise and a seeming rise. Some lines do actually "go" up, while others are more like vapors emanating upward from a given pitch.
In the same way that up and down may be ambiguous in terms of pitch motion, the matter of up and down beats can be just as confusing. The mere presence of a bar line on the page does not indicate a clear downbeat, despite what you learned when you were nine.
Again, good composers go out of their way to ration the down-beat quality.
The better the composer the greater the challenge and the more honesty it takes to recognize the problem and imagination to deal with it.
