For those of you who play higher level games, what about the high level content in the phb do you like? Most classes just seem to get improved or scaled-up versions of their signature class abilities (e.g. song of rest d10 then d12, extra attack, more uses of a particular feature, etc.). A common complaint I see is that there isn't a lot of customization past a certain level.
Even though customization isn't as frequent in the upper levels, the amount of unique, interesting, and fair scenarios increase.
It would be quite a bold move for the DM to introduce a infamous and violent Ancient Dragon to a campaign where the party would struggle against an encounter against a CR 10 threat, but at higher levels, not only could they stand a chance physically, they could also have influential and political strength as well. Suddenly, this awesome dragon that would have had to be put on the sidelines or weakened beyond the reasonable expectations of the story can now play a part that's true to that dragon's nature.
More succinctly, your party can face the fiercest and deadliest challenges without being given a handicap. And that feels awesome!
Being the fighter that solo kills a dragon's lair, being the wizard that trades ancient secrets with entities from a different plane, being the rogue that has stolen several kingdom's worth of treasure with ease, or being the paladin that has his named forever etched in the holy scriptures of his religion.
These are feats that are either unreasonable or impossible for low level characters yet its almost an expectation of higher level characters. That's what makes high-level play...
EPIC! (Sorry, had to let it out...)