Weightlifting requires a precise balance of strength, power, agility, balance, and coordination. The lifts takes years to master and CrossFit ranks weightlifting near the pinnacle of athletic development.
As you become more proficient at these lifts, you will be able to lift more weight during workouts. Which means you will perform more total work. Which means you will be fitter!
Stop being frustrated by these lifts. Try the Olympic Weightlifting class!