Another classic mistake is transforming into a gym rat overnight. You've signed up for a gym membership, bought new workout gear, and you're ready to crush it. The first day, you go all out—running, lifting, squatting—until your legs feel like jelly. The next day, you can barely move and suddenly the idea of exercising feels like cruel and unusual punishment. Instead of pacing yourself, you burn out faster than a sparkler on the Fourth of July. Remember, Rome wasn't built in a day, and neither are six-pack abs.