Why not? Do you enjoy re-inventing the wheel? if not jQuery, why not Dojo? Or YUI?
Writing complex script on pages without the aid of one of the useful libraries is not wise. These tools abstract all the complexity and cross-browser nuances away for you.
If you write Java, do you use the Java collection classes? Or have you implemented your own List and Map implementations? Do you write your own JDBC driver?
Availing yourself of the available tools is a good practice.
I know this is a year old post, but it does shows high in google, and since I registered just to answer the last post, well, I hope my comment will stay here
Honestly, I also don't use JQuery. It does makes life simpler, but loading a 90kb file on a page just to do simple stuff like opening a popup page with a customized page, or adding some dynamic things to a website is a waste of bandwith. Of course, you can load it from another server, like google, but the problem is, what if google's server is busy, so your site's loading will late because of that?
So DO go back to basis and reinvent the wheel because that's the only way you will be different than others and have a better website than others
Sorry for the long post ..... I just had to throw this out of me Not with anger but with joy. Hopefully nobody feels attacked
Welcome to CodeRanch!
On the points.
3) What works in IE does NOT run everywhere else. I've been burned by that enough times to always test in at least two browsers.
4) jQuery is loaded from a CDN (content delivery network) - google's server as you noted. It's then cached on your browser. This turns out not be a huge performance hit.
6) I don't want to have "better" confirmation box than everyone else. I want it to be what users expect.
It's fine for you to choose not to use jQuery. But it's also valid for Bear to recommend it.
Is it possible to re-invent the wheel? Sure. If no one did, there'd be no progress in inventing better wheels. But not everyone has the time or the expertise to build a better wheel.