The squat is probably the single most value-for-time exercise, but you might hate it if you started with the wrong variation. Or you might be bored with it if you haven't taken it to a new level. Here are the progressions from beginner to advanced.
Let's break down each variation:
This is the best starting point for beginners because it's intuitive and simple to learn. Use a dumbbell or kettlebell. Place your hands directly under the weight while keeping your elbows tight to the body. Get your feet slightly wider than hip-width with your toes angled out a bit. Now just squat down until your backside touches a medicine ball.
The goblet squat is front-loaded, which reinforces correct positioning: chest up and back flat.
Once you've mastered the basic goblet squat, introduce the barbell. You can learn the zombie squat in just a matter of minutes. It's a great progression to teach new lifters the proper front-rack position. Use a squat rack to set the bar.
The zombie squat allows the bar to rest across the shoulders/clavicles instead of in the hands. Once you get a feel for the zombie squat, simply get in a front rack position if you have the mobility, keeping your elbows high and hands/fingers around the bar.
The front squat will build leg, core, and upper-back strength. It's a must if you want to do any Olympic lifting or CrossFit.
It's the best exercise for developing both strength and muscle since it's the variation that allows you to lift the most weight. But it's best to learn the back squat after you've mastered the front squat and dialed in the proper squat mechanics and foundational strength.
The overhead squat is the most advanced variation. It requires a high degree of overhead strength and mobility. It's another one you'll want to learn if your goal is to do either Olympic lifting or CrossFit.