Sketching in Seattle's coffee shops

So I feel like I lost the flow of this thread a bit, and turned more to doodling and posting in that thread instead, I think maybe because I got a bit stumped by different styles, mediums or topics to try… so… any suggestions?! What should I sketch, is there a type of material, style, topic or anything that you really enjoy that I should experiment with? Is there an exercise that you think really benefitted you or taught you something? Is there a style that you’ve replicated that changed your whole outlook on sketching?