If you have a higher speed Internet position this might not be a problem but if you have slow internet and want to watch youtube videos, Youtube's buffer method is really annoying. Youtube by default has Dash Playback enabled. Dash Playback is the way a video is buffered. When enabled, every time you forward a video in youtube, it will rebuffer from that position. When you turn off the Dash Playback, you can pause the video and let if buffer. This way, you can jump around the videos as much as you like. YouTubeCenter is the way you can opt out of it. Apart from fixing this, YouTubeCenter also removes ads and comes with lots of customization. YouTube's left alignment is fixed to center as well as comes with lot of customization option. 

--> How to install in Mozilla Firefox.

1. Since this is a user-script make sure you have Greasemonkey monkey. If not .. install from here.

 https://addons.mozilla.org/en-US/firefox/addon/greasemonkey/

2. Install YouTubeCenter frome here...

http://userscripts.org/scripts/show/114002

3. Clicking on Install will prompt a confirmation box from Greasemonkey.

4. Click install.

5. After the confirmation message, Open youtube

and go to settings.

..-> Dash playback is enabled by default as well so uncheck the box.

After unchecking it, you should be able to let vidoes buffer and jump to any minute in video.Also, ads are removed and youtube looks much better. Also check out other customizations it has to offer.

Learn more about youtubeCenter here.

https://github.com/YePpHa/YouTubeCenter/wiki#

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For Chrome:

download the add-on from here
http://userscripts.org/scripts/show/114002

1. Go to settings > Extensions > Enable Developer Mode.

2. Drag and Drop the addon file you just downloaded to the extensions page.

3. Confirm the installation and you should be done.

Happy Youtubing...