The quote draws a humorous parallel between running and coffee. "Running is like coffee" signifies their shared impact. "Nicer after I've had one" implies a mood improvement. The quote humorously suggests that, like a cup of coffee, running can boost one's mood and make them more pleasant to be around.
The quote underscores the mood-enhancing effects of physical activity. It highlights the idea that exercise, in this case, running, can have a positive impact on one's disposition. "Nicer after I've had one" reflects the emotional benefits of a run, which can include stress relief and an uplifted mood.
In essence, the quote humorously likens the mood-altering effects of running to that of a cup of coffee. It conveys the idea that physical activity, like caffeine, can have a positive impact on one's emotional state, making them feel more pleasant and approachable after a good run.