Some old gurus or Confuciuis wannabes will tell you that something excessive is bad. It is true if what you are being excessive about is bad. If you are drinking alcohol too much, smoking too much and taking steroids too much then it is bad. There is no other explanation needed, it is bad for your health and when you take it excessively then you may die or be hospitalized for months.
But what if what you are being excessive about is good then what is bad about that? if you are obsess in exercise or making money or helping the less fortunate people, is it really bad? I don't think so.
It is bad if it is doing damage to your body and brain but if not... then go ahead and be mad about your passion, escalate it to the highest level. Go to the extreme so you will know how far can you go.
Great people do excessive things that is why they became successful. They were very excessive to the point where others can't do what they can do anymore. They train very hard, work very hard, they don't even know what is excessive anymore. They go to the extreme, they make it to a point where they were very close to being perfect. And in the end... they get very big rewards, so now tell me what is bad about being excessive?
And if being excessive is bad, how about doing less? how about exerting a mediocre effort? How about knowing that you can do more but you are doing less? isn't that bad too?
As long as it is giving you results, as long as it is giving you success then keep on doing it. Never stop because nobody knows what is the limit of your body. You know when to stop, you know when it is not healthy anymore. You know yourself more than anybody does so as long as your mind says keep going then keep going.
And people who wants to take rest or wants a comfortable life with poor results always make the word "excessive" as an excuse. It is simply because they don't want to keep going anymore. They will also tell it to everyone that it is bad to go very far because they don't want to be left behind.
The conclusion is the word "excessive" doesn't even exist because our body and mind has no limits. It is up to you if you will accept that you have had enough. But always keep in mind that if your mind says keep going then it is time to keep pushing.