I have to agree with HVEECK, on several points.
1. It is very hard to get to the point where you look 'buff'. You have to build a significant amount of muscle (hard for women, because we don't have testosterone) AND get your body fat pretty low. If you're worried about waking up wake day and saying, "OMG! I look like a man!"...don't worry, it won't happen.
2. People at the gym are there to work out. No one's watching you. If you do visit a gym and there are people preening and trying to get dates (there's one near me like that), just join a different gym.
3. I have found the classes at the gym to be very helpful. It forces me to work harder than I otherwise would, and try different things. I've said it before, but I also love the community aspect of classes. Going there every day, seeing the same people, chatting--it appeals to the social side of me, that working out on a machine by myself doesn't affect.
4. The biggest benefit is the variety of equipment at the gym. I can do cardio at home, but I certainly donn't have the three machines that I like at home. And I definitely don't have the weights at home that they have at the gym! Even the Bosu ball--to buy one costs over $100. For cardio, I could keep running and biking to lose weight, but I would definitely need to motivate myself more, since I would be bored more.
You can definitely lose weight without a gym. I lost the first 20 pounds just by doing cardio on my own. However, I lost the last 20 (okay, 17 pounds so far) after joining the gym near my workplace. Now I'm getting compliments on how fit I am. A couple months a go, a male co-worker I'm friends with noticed me in a sleeveless shirt (it was warm in the office that day) and commented on how good my arms looked. And a female co-worker who has been going to the gym too said she told her husband she wanted calves like mine. That wouldn't happen without the strength training I'm doing, since it's the muscle on my body that makes me look fit and "toned."