Coffee Appreciation

Sometimes when I order a Cappuccino there is so much foam left at the bottom, i'd need a spoon to finish it but sometimes this doesn't happen im left very disappointed.

What is the barista doing wrong when this happens?
What do I need to ask for to insure my beverage drinking is completely fulfilling.
I mainly drink coffee just as an excuse for foam
(not sure if this will end up being the right thread for this)

It's to do with the amount of air added while the barista stretches the milk. What you ask for will depend on what kind of foam you're after. If you ask for a dry cappuccino, most of the time you'll get big bubbles and airy foam, if that's what you want. The alternative, if you want that really nice creamy textured milk, like a latte etc, but just more of it, maybe just ask for thicker foam. Obviously everywhere will be different. I reckon your best bet is to communicate with the barista! Just let them know what you'd like, and they can hopefully recommend the best way to get it from them!