I am a Bachelor student in Computer Science and hobbyist web developer, experienced in html css3 js regex and a beginner in svg php python c++. I like to think outside the box to find alternative uses for existing features, such as with my CSS3 mineturtle, or with this supposedly impossible question.
I came up with CSS3
:checked-based tab menus independently in 2011 (back when IE8 was still by far the most used browser).
A personal dislike of mine is jQuery UI's default styling being used so often without being customised. The visited item on your own userprofile that shows the dates you logged in, for example, just doesn't blend in with the other styles at all.