My experience of making espresso based coffees with an amazingly well informed and experienced barista. There are so many nuances that make a great cup of coffee that it's hard to pin it down. I used the same fresh beans, same machine, same water etc etc and his coffee tasted a world better than mine because he had the timing and technique to making down. He explained and demonstrated that even small things like how densely you pack the coffee in the filter basket makes a considerable difference. It was an eye opening experience.