"不要听那些哭泣和抱怨的人，因为他们的疾病是会传染的。"

Simplified Meaning:

This quote is saying that you should avoid people who are always negative and complaining because their bad attitude can affect you too. Think about it like this: if your friend is always grumbling about how terrible everything is, you might start feeling the same way, even if you were in a good mood before. It's like if someone has a cold and spends time with you, there's a good chance you'll catch their cold. In the same way, spending time with people who are always negative can make you start feeling negative as well. So, to stay positive and happy, try to be around people who lift you up and have a good attitude. This way, you keep yourself in a healthier state of mind. For example, if you have a positive friend who faces challenges with a can-do attitude, spending time with them can encourage you to do the same.