There are some players who like to treat their favourite spell as the all-purpose answer to everything. It's usually something destructive, like Fireball.

Orcs are attacking? Cast Fireball!

The evil knight is kidnapping the princess? Fireball!

We need a way to cross the river? Fireball!

So when players start coming up with reasons why their favourite spell might not be perfect for some occasion, best not to argue.

Transcript

GM: Unfortunately, the droid army has beaten you to the city.
Obi-Wan: From the other side of the planet?
Qui-Gon: They probably took a shortcut.
Obi-Wan: We go to the royal palace.
GM: It's surrounded by droids.
Qui-Gon: We attack.
Obi-Wan: Do you want the whole army to attack us?
Qui-Gon: Imagine the loot!
Jar Jar: Wesa can sneak in. Mesa knows a way!
Obi-Wan: Good idea, let's go.
GM: You reach a balcony. You see the Queen and her retinue being led away by combat droids.
Qui-Gon: I cast Summon Bigger Fish.
GM: What?
Obi-Wan: What?
Qui-Gon: I roll 17. I drop it on the droids!
Qui-Gon: Oh wait, no... can I take that back?!
GM: Um... Sure.
Qui-Gon: That'd just be wrong.
Obi-Wan: I concur.
Qui-Gon: It'd stink up the palace for a week. Then she'd never give us a new boat!