My parents are extremely strict and it makes my life difficult. Despite being 18 years old I still have to be home by 8 pm. I don't get involved with anything haram but every time I want to go out, which I rarely do, I get interrogated and harassed with a hundred questions. How should I handle this situation?

Islamically you are allowed to leave the house when you want to. However, Islam commands us not to hurt our parents. If coming back late hurts them, you must avoid hurting them. I recommend the following:

1- Have an elder or a friend whom your parents respect talk to them and tell them it’s ok if you return late. This person can ease their concerns.

2- Have a calm and respectful conversation with them. Ask them what their concern is, and try to address those concerns. Let them know exactly where you’ll be and whom you’ll be hanging out with. They might fear that bad friends will influence you. Let them know whom you’ll be with.
And don’t say things like “I’m an adult I know what I’m doing.” Say something like, “I appreciate your concern about me. And I thank you for that. What guidelines do you have for me if I want to come back after 8?” Just ask them about that and they’ll be more willing to discuss it with you and giving you some freedom Insha’Allah.

3- Be patient. Your parents love you and it’s out of their love that they’re overprotective. There are a lot of dangers out there in society, and so they are concerned. Try to appreciate them. They are no deliberately trying to harass you, but they are just concerned, so don’t take it personal.