Is it normal i hate the left alt + arrow key combo to navigate pages
As a power user on Windows using the Chrome browser I was used to hit backspace to go to the previous page. Relatively recently google changed it because many people occasionally lost an entire form's content if the focus was not on the edit control (text area in html parlance) and they wanted to delete one or more characters.
This is true, I had it happen to me as well though not that often that it warranted changing what was years of UX.
What bothers me the most though, is WHAT key they decided to use as a replacement. Why the LEFT Alt key + arrow left keys? That means I have to use both hands and can no longer be holding a beer can or coffee mug while surfing anymore. You just have to put it down so you can use both hands. If they insist on a key combo rather than a single key why not make it the Alt Gr (right alt) or maybe even right ctrl + arrow combination instead? It isn't rocket science dammit.