Odds of Getting In
When all you need is to have a good attitude and for a manager to like the cut of your jib, it's not too hard to get in. There are a million different coffee shops to apply to. If you get rejected by one, there are a hundred more you can apply to.
Even if one rejects you today, they may hire you tomorrow because one of their baristas quit to follow her career dreams on Broadway. There's a high turnover rate and almost no qualifications are necessary (source). If you can't get a job anywhere as a barista, you may have to re-evaluate that hat you keep insisting is "great" luck.