What bad things Lennie does in the novel?

Lennie, the gentle giant from John Steinbeck's *Of Mice and Men*, is a complex character. While he's kind and loyal, he also struggles with a severe mental disability. Here are some of the bad things Lennie does, stemming from his lack of understanding and control:

* He accidentally kills mice and a puppy. Lennie loves soft things and pets them instinctively, but his immense strength makes him accidentally crush them. This highlights his inability to understand the consequences of his actions.

* He accidentally kills Curley's wife. Lennie is deeply afraid of being alone and is drawn to the attention Curley's wife gives him. When she asks him to touch her hair, he panics and grabs her, accidentally breaking her neck.

* He causes trouble for George. Lennie's actions constantly put George in difficult situations. He needs constant supervision and often puts George in danger, especially when he tries to hide the dead puppy and when he accidentally kills Curley's wife.

It's important to remember that while Lennie's actions have terrible consequences, they stem from his disability and his inability to fully comprehend the world around him. He is not inherently malicious but rather tragically flawed.