What's the hardest instrument to play? (In your opinion)?

I play flute, singing, recorder, piano and my sister plays the clarinet. I would say singing is the hardest, you have to worry so much about pitch and techniques, with an instrument you just have to press the right keys or bow the right notes. With singing you have to keep in pitch and support and there are so many things to remember. Next i would say the piano because you have to learn two parts and play them at thhe same time. Then trumpet because its so hard to make a sound on it. Then sax (making a sound on a sax is also very difficult), violin (because bowing and not sounding like a dying cat is something not many people achieve), cello (for the same reason as violin), flute (at the beginning the flute is virtually impossible, it took me three months to make a sound on the flute), clarinet (making a sound without squeaking is very difficult and it takes a lot of air to blow the clarinet) then recorder because it is really easy.