Sometimes, people don't want to do something, even if it's important or helpful to other people. This is called "obstructionism." It's like when your friend says they don't want to play with your toys, even though you really want them to.
In politics, obstructionism happens when people don't want to let an idea or a law go forward, even if it could help a lot of people. They might not like the person who came up with the idea, or they might not like it for other reasons. So they do things to try to stop it from happening.
For example, let's say that some politicians want to pass a law that would help people get better health care. But other politicians don't like the law, so they might try to make it harder for it to pass. They might talk for a really long time to stall the process, or they might try to add things to the law that would make it worse. They might even refuse to vote on it at all, so that it can't become a real law.
This can cause a lot of problems, because it means that important things don't get done. It's like if your friend kept saying "no" every time you asked to play a game, even though you really wanted to. It can be frustrating and make it hard for people to work together.