The article explores the habitability of 85 known extrasolar planetary systems by studying how the gravitational pull of giant planets affects the stability of potentially habitable terrestrial planets. Results show that over half of these systems are unlikely to have habitable planets due to the influence of distant, eccentric giant planets. However, about one-fourth of the systems, including some potential targets for finding Earth-like planets, are as dynamically habitable as our solar system. Some habitable planets in simulations have significant eccentricities, which could impact their habitability by causing large seasonal climate variations.