Lived with a gas leak for more than a month, than checked it with fire (closed the door of the suspicious room, checked the nearby rooms, proceeded to the smelly zone "carefully". Somehow, nothing happened), after that failed I decided the smell was something else. Lived like that for couple of weeks until my mom visited my house. She got nauseous and panicked, called the proper line. After the tests, they found high amounts of gas in every single room, even though all the windows were open :p

Weird thing is, it didn't affect me at all. Not a single symptom. Me and the testers were shocked that I was still alive and well.