How do you spend your time in an idle working day?

Today is a typical working day, nothing special happened. but there was a little bit busy the whole afternoon, searching and fixing some bugs, and finally all were done.

My position is software engineer, but the job seems that there's no challenge to do, no new development to do, just maintaining the old. So I can take the opportunity to learn English, it's nice!

I peeped on other colleagues' screens, it seemed like they were surfing the Internet for no reason or reading novels on the Internet.

I think it is not good for a job to be too busy or too idle. Actually, it depends on how you spend your time, benefited or wasted.