I hate browsers every single one that I've used. Every browser out there is a pathetic failure when it comes to user interface. Right now my favourite browser is iceweasel/firefox but in my book it doesn't have much going for it.
The browsers have a love for pop-up-dialogues. It's getting a little better but not good enough. I remember when in firefox if you mistyped a URL it would pop a dialog box "Server not found." So you'd have to take your hands of the keyboard and hit OK and then put the cursor back to the address bar and try again. Why does the browser need to confirm with me that I mistyped something? Now this is no longer a problem; when you go to non-existing page you'll get a message insider your browser pane saying that server cannot be found. This is great but I believe that NOTHING should pop-up without the users intent
Say, for example to search for something on google and you get a link to a mailing list. I've seen a few mail-list archives where they use self-sign signatures (https) so you get a pop-up dialogue saying that the page is not kosher. WHY?! Its not a page I care about for security; in fact most pages I visit I don't care much if the anyone spies in on what I read. I think this warning should be brought up where it can be ignored without any user interaction. For example a drop down bar with a message (like those pop-up blocked notice). Heck you can even turn the whole browser panels and things RED so even the most senile users will notice something strange is up. And maybe the first time the user comes across this error it should pop a dialogue explaining why the browser miraculously turned red.
Users hate dialogues if it has more than 200 or so characters in the message a majority of the users won't even read it, they will in a robotic-type fashion click on some button until the dialogue will disappear. So, just stop with the pop-up dialogue boxes they are annoying and not useful. If your program needs to constantly pop things up for user to select then you have failed user interface design.
Iceweasel/Firefox has this awesome feature where you can scale the page fonts. Its incredibly handy when you come across a web 2.0 website with 2 point font (fucking web designers, readability first style second!! STOP IT!!). Now this is all fine but I am tired of always manually adjusting the fonts per website. Fortunately there is other great feature (Edit>preferences>content>font&color>advanced>minimum font size) where you can set the minimum font size. Well you'd think this is the best thing since sliced bread (figure of speech, I hate sliced bread too but thats for another day) but there is a tremendous flaw with this feature. When you select a minimum for of size, say, 8 every font thats less than size 8 will be turned to 8 all larger fonts will not be affected. This sounds great in theory but horrible in practice, if you got to some heavily stylized graphics your setting will send a lot of fonts out of boundaries. So you'll get overflowing menus, notices and all that other jazz. Its so annoying its that its not usable. What the browser should do instead is scale all the fonts on the page. Say the smallest font on the page is of size 5 then 8-5=3 so increase EVERY font on the page by 3 points, kind of like what happens when you use manually adjust font size (view>text size>increase).
Stupid menu-bars. Every browser is full of them. You have the status bar on the bottom the menu bar, search bar, tab bar and bookmark bar on the top, WTF?! When I use the browser I want to see the webpage not the static content of the browser. STOP stealing my real estate. So I suggest you disable the bookmark and the status bar. And you'll scream BUT I want the functionality of my status bar; "I want to know where the link points that I am about to visit." Well so do I, I hate the bar but like the functionality it provies, but there is nothing to say that the functionality can't be moved. Say when you move your mouse over a link your address bar displays the address of the link, and as soon as you move away from the link the address bar goes back to displaying the address. As for the load status, I've found this great plugin called fision which takes from a safari feature, shows the progress of the loading in the background of the status bar.
The great menu bar, its immune from any customization. I just sits there, does nothing most of the time, face it how often do you use it? While its very useful its not needed all that often (maybe once a week) so why is there not a feature where it can collapse into a expandable menu (kind of like the start button on windows or kmenu in kde) And when you click this monster it would just appear. Now allow this menu button to be place into any other panel and forget about. What a real estate saver.