By far, the most effective motivation to concentrate on and learn something is being assigned to debug/add features in a language/stack I’ve not used yet. While this certainly lights a fire and gives me the concentration I need to learn how to get the task done I do wish I had more time to follow up with “now that I’ve done X in language Y and platform Z, I’d like to loop back and actually learn language Y and platform Z — but I have a new assignment...”