If you're tired of the same old peanut butter and jelly that you've been eating every day and want to get out of the food rut you're in you should take a look at how sandwiches are made around the world. Sandwiches don't take a lot of effort to make, no matter what the ingredients, so they're a great way to expand your diet no matter how skilled you are (or aren't) in the kitchen.

Classic, Vegetarian as Well Non-Vegetarian Panini Recipes Easy to Make - Different Versions of Healthy Panini Recipes for Kids and Adults
In Middle Eastern countries (and Greece) it's popular to make sandwiches using pita bread. Pita has become much more popular in the United States in recent years, so it should be an easy thing to find, and usually lower calorie than using traditional white bread. Probably the most popular pita sandwich option in the Middle East would be Falafel (balls of chickpeas and spices that have been deep fried or cooked up in a pan with oil) sometimes paired with cucumbers and topped with a yogurt dressing.

The Bánh Mì is a Vietnamese favorite, often eaten at food carts. It's made on a baguette with mayonnaise (sometimes paté), pickled vegetables, some fresh herbs, and filled with different things, including tofu, eggs, chicken, or barbecued pork.

The state of Maine has a unique summertime sandwich that is sold in sandwich shops along the coast. They're called lobster rolls, and are just lobster meat mixed with mayonnaise and put in a bun split down the middle (these are usually nicer buns, but a hot dog bun works just as well).

A traditional Italian favorite that has become a favorite in the United States and across Europe is the panini. Traditionally in Italy this really just means sandwich, and is often a sandwich with some meat and cheese with oil or butter spread on each outer side before toasting it on a grill on both sides. These days panini has come to just mean a sandwich grilled this way, and all types of fillings are being put in these sandwiches and grilled up. It's really become a way to take a normal sandwich and make it special by grilling it.