The location of edge (arrow) labels seem to always be on the top for horizontal edges, and on the right for vertical edges. It would be nice to have a way to specify which side the label is on for each edge. Also, I'd expect this to be more of a generic features (i.e. any type of diagram with arrows could use it).
Ex.
@startuml
(this) -> (that) [bottom]: something cool
(this) --> (those) [left]: bad times
@enduml
