When I hear things like, "a lot of stuff". I feel like the speaker is hiding something from me, maybe an important detail. Because a lot is a generalized word, and so is stuff. When you have a lot, it is not specific. We do not know exactly how much you have, we can only speculate. While stuff is the same thing, and it is commonly used. People make sentences with stuff as if they have given you the details before.
When I hear such statement as the prompt, I just take it you don't want me to know the details of what you are talking about. I don't pry either.
You can also participate by clicking here