If there is one thing all WoW players agree on, it's that Blizzard tooltips are usually very bad. They contain too much fluff, too many unnecessary numbers and overall a lot of "nerdy" information that nobody can make any use of. With Enhanced Tooltips, all spells and items will simplified to be human-readable, see the example below.
Before Enhanced Tooltips:
After Enhanced Tooltips:
You can open the options menu with "/enhancedtooltips"