1. "I spend a lot of time on the internet."
2. "I spend too much time on the internet."
The first sentence just states a fact, but the second sentence implies a problem. "Too much" indicates that the speaker wants to or thinks that they should spend less time online. The reason it's important to spot the subtle difference is because, while the second person may want to change their behavior, the first person may just be stating their behavior. Much of the time, we hear these sentences as if they are the same. We interpret "a lot" to mean the same as "too much" and start offering the person advice when they don't want it. And it is very annoying to have someone try to change your behavior when you never said that you wanted to change.
I have gotten a few responses along the lines of, why would you bring the subject up if you don't want to change it? That doesn't make sense to me. Is it only socially acceptable to discuss things you want to change? People talk all the time about things that interest them, things they've done, things that have absolutely nothing to do with changing. Being told that you shouldn't bring up the subject just means that the subject is something that most people won't accept.
Although I don't agree with it, I do avoid bringing up certain subjects if I think someone will try to "fix" what is not a problem, but some of these things just come up. Someone wants to meet at 7:00 a.m. on the weekend and I have to tell them that I sleep till noon. Someone has a dog and I have tell them that I don't want it anywhere near me. We just can't always get around these topics, and we shouldn't have to.
A person's tone of voice, word choice, and the context of the conversation can give clues as to whether or not something is a problem. If you're uncertain about whether a person wants to change, you can always ask something like, "Do you like your schedule?" But don't just assume that someone wants to change when they have merely stated a fact.