It's not an infrequent question. There's a discussion topic here:
Of course, there's no definite answer. My personal 7 are:
ii. The fact that Koga and Janine's scarves always look like they're blowing in the wind.
iii. The amount of Pokemon shippers there are.
iv. How the tables and cooking equipment magically appear when Dent makes meals in the middle of nowhere, despite only carrying a backpack half the size of his torso.
v. Officer Jenny and her lack of usefulness.
vi. Did the Pokemon or the egg exist first?
vii. Ash's stupidity.
If we're talking about places:
i. Temporal Tower
ii. Cinnabar Island
iii. Safari Zone
iv. Brass Tower
v. Mt. Coronet
vi. Celestial Tower
vii. Chargestone Cave
That's my serious answer. :I