I am glad you two noticed that really good tequila is very smooth! That's why in the US I only buy high quality tequila.
I was told that all low quality tequila in the US is diluted not just with water but other substance too. I didn't believe my patient until he came back from Mexico and gave me a new bottle of Gustanos de Oaxaca tequila. After I healed him, he thank me by giving me a bottle after visiting his parents in Mexico.
This no name brand Tequila is very smooth! I can't even taste the alcohol in it!