You didn't ask, but I'll tell you how I make a grilled cheese with normal cheese. I have never experienced "lumpy and gross", but perhaps this is left to the individual.

Choose your bread. Anything you desire. Choose your cheeses. Nothing wrong with mixing it up and using different cheeses. If you have one of the cheese platters in the house that has a variety, this is the prime time to make a grilled cheese. Butter the pan and lay down your first slice of bread (medium-low heat). Lay whatever cheese you like on the inner side of the bread (season if desired). Let the bread toast and the cheese will soften, but you can cover it to let the heat build up enough. Not too long though as you don't want moisture building up. Throw your second slice of bread on top when you want and when the bottom side meets your expectations of toasty, flip the sandwich (during the flip, I flick more butter in for the fresh breaded side to begin its toasting session). You are now faced with the toasted side. Take more cheese and place it on the toasted side. I often use parmesan or asiago (you can use any type), but do not use a lot here. When the second side is toasted to suit, flip it back on to the outer cheese side so it can melt and toast again. Then ply the second toasted side with cheese and flip when the time is right. You will have a nicely toasted cheesy side now with the second toasted cheesy side.

You can season with garlic or garlic salt or some other herb or spice you enjoy. I love making grilled cheese sandwiches like this. They seem fancier and definitely have more flavor. I also welcome any constructive criticism or suggestions to help "up" my game further as I am always looking to improve.

That's why you eat them hot. I never use "American cheese" of any variety in a grilled cheese, I almost always use cheddar, and occasionally throw in some form of jack (Monterey Jack, PepperJack, etc). The trick is to cook it on medium-low heat and cover with a lid so it thoroughly warms the sandwich, if you cook it too hot w/ the lid off, the cheese doesn't heat enough to properly melt.

You can use fancier cheeses in a GC too, but you still need at least one slice of fake cheese for proper consistency. It's the immulsifiers.