Do I put too much thought into making characters? Do I really need to be concerned about things like their height or weight or favorite foods?

In my opinion, better to err on the side of extra detail than too little; I mean, imagine if I wanted to make a restaurant scene - what would everyone eat? If I knew what they liked to eat ahead of time, I could concentrate on developing the story rather than getting stuck on the menu.

Think about it - why are fan-made universes so common and parodies so popular? One reason is because both the author and the audience knows what to expect from the characters they know. The one or two new characters that the author has to make from scratch are usually self-inserts or based on stereotypes (emo, Mary-Sue, etc.).

Those that make honest-to-goodness interesting fan-characters usually think about the details. Their dreams, their fears, their secret motivations, those little quirks to their personality that make them recognisable from a well-made fake - these things are what the serious author has to think about. Sure, the audience may not see all those things, but if the author wants to make a story that features interesting character development and shocking surprises that make perfect sense in retrospect, they have to think about the characters in detail.

[EDIT]
The principle of details can apply to more than just individual characters - it can apply to landscapes or cultures, too. Subtle color schemes differentiate the ice cold mountaintop cavern from the toasty volcano alocove. Certain styles of music remind us of the Arabian market, others of the Egyptian pyramids. The settings are similar - both are caves or deserts - but the subtle differences give the viewer/listener a totally different idea of the situation, and they will anticipate different things to happen.

If the Arabian Nights theme from Aladdin was playing, would you expect mummies to appear? If the Sandopolis track from Sonic & Knuckles was pumping through the speakers, would you expect to find a wish-granting genie in the next room? Choice of background music can influence viewer's expectations in a flash - sometimes in subtle ways.