Well, in another post regarding treestands, I have seen the comment made several times that the hunter is hunting too high in the air. As long as the aforementioned hunter is comfortable, and attached to a fall restraint system, why not? No one ever comments on WHY it is too high, just that it is.
So, what, in your opinion is too high, and explain why you believe so.

(self explanitory)
I think when my platfom grips the tree but my seat slips off the top that's too high.

There is such a thing as too high. Depending on terrain, you can get to a height to where the angles get "worse", or more severe, with each inch you climb. In a perfect set-up, all shots would be flat. However, we all know that getting up in a tree conceals movement, scent, and sight. Once you get high enough to achieve this, I feel you are only hurting your chances by ascending any further. There is not a harder shot in archery than shooting straight down on a deer between the shoulder blades.

Anything above 30 feet is too high in my opinion. I used to be one of those that was against going anywhere above 20 feet, but after reading several articles concerning string jumping, I changed my mind and my habits.

I'll try to paraphrase what I learned and make it simple enough to understand.

When you're hunting from a lower stand, say 12 - 20 feet off the ground a deer that 'jumps string' will be jumping out of the way of your arrow. If you're in a stand 25 - 30 feet off the ground a deer that jumps string, due to the angle of the shot, will be jumping less away from you and more toward you. You've got less of a chance of making a poor shot on a nervous deer from higher up.

I realize that probably makes absolutely no sense the way I wrote it out, but the article made it clear. I'll see if I can't find it. If I remember right it was an article written by Chuck Adams. I'll see what I can find.

To high is when you can't lean back in your climber because it is slanted down so much. I like to sit 30 ft give or take whatever will give me the best shot.

This is what happens when you go too high. It all depends on how far the shot is though.

i climb til i feel comfortable or my pull up rope is maxed out which is about a little of 25 ft....

Quoted it to fix the image.

Hunt how ever high you want. You want to talk about string jump?? I have killed deer 15 feet in front of me on the ground. No deer is going to jump the string at 15 feet with 303 feet per sec. compound bow. So if you don,t want string jump get up close and personal. I usually have 3 tree stands and several ground spots and I would say my kills were about equal tree versus ground hunting. But the tree shots were a whole lot easier to pull off.

I usually stop climbing when my nose begins to bleed or when I can wave to pilots.