Internet explorer is too slow to operate and browse compared to modern browsers like Chrome and Firefox. Reliability, multi-tabs and user friendly addons are the main characteristics that make the others superior compared to IE.
My main gripe has been the need for extra web development to make websites appear the same in IE as in other browsers. That said, the newer iterations are better, and Spartan is pretty darn alright - but still isn't likely to replace neither Chrome nor FIrefox for me.
Well, as a web developer IE is very hard to work with since it doesent support a lot of things like the other browsers though. Hopefully now though with the release of W10 the new browser will be up to par with Chrome, Firefox etc.
Maybe because of not being too user friendly. Internet explorer is not that user friendly. The protection level of internet explorer is a bit low. Plus it really a bit slow than the other web browsers.
The reason for internet explorer not being liked by many of the tech savvy people because of its not so cool interface and lagging speed and detailing. But enough efforts have been done by Microsoft to improve the browser, still Mozilla, Chrome are liked way too much to be competed with.
One of the reasons is because during all the time when IE was essentially the only browser (after first browser war in 90s and prior to mid-2000s) Microsoft implemented standard in a way they wanted, regardless of how features were supposed to work according to said standards. Thus, IE often doesn't follow, say, CSS specification, and web designers have to implement special workarounds to make things work as intended.
Also it was really slow, unsecure and unstable. I don't know if IE became better nowadays (I have never actually used it anyway).