People always ask me why I don't use one of the big frameworks like jQuery, Prototype, Mootools, YUI etc. My answer is that its not that I don't think their code is good although I have found numerous bugs or issues in all of them over time but rather that I prefer to write my own code because that way I get to understand the language and become a better coder.
For example on a project I worked on I had to create a fading in lightbox WYSIWYG editor that could float around the screen but never leave the boundaries of the viewport. This is no easy job for a novice and I could have easily loaded up Prototype, Scriptalicious and TinyMCE, found a how to article on Google and got the code working with a few hours. However I would have no idea how the code worked and if I had to make customisations to the code I would then have to spend hours trawling through lots of code I didn't understand hacking about until my tweak was complete. Plus I would have to do it in a way that any updates to those libraries didn't overwrite my changes when future updates were rolled out.
Obviously if you have time constraints or just don't care about how things are done but just want them done in the quickest way possible this maybe the way forward for you and I don't blame you for not wanting to commit the time it would take to build a widget such as the one described from scratch. However this is what I chose to do and it involved spending some considerable time reading up about my intended task before even attempting to write a line of code for the job.
This method of development will take you some time to achieve and you will probably spend a lot of time pulling whatever hair you have left out of your head. However along the way you will learn a lot about your craft including browser differences, the history of the DOM, event models and future developments as well increasing your own skills as a developer.
The pain and time spent will be worth it as when it comes to getting a high paid job in development in the future you will have done yourself a big favour by going down the hard route. Plus the widget or application you have just built will be your own creation and you will know your own code inside out. Any bugs that need fixing will not rely on some 3rd party to release an update and you will have pride in completing a job that many others would not do.
Now I am not totally against frameworks and even use a couple on my own sites. However I do feel that people tend to use them without due consideration to what tasks they actually need to perform. If you are writing heavy DOM manipulated AJAX application that utilise the majority of JQueries features then that is the tool for you. However if you are not intending to use the majority of the features and just like the fact you can access an element by id with the $ sign then you have bloated your codebase unnecessarily.