Who doesn't love the player who wants to be able to do everything with no limitations? Here we have the Greyhawk version of the OD&D elf, with the new multi-class concept of fighter / magic-user / thief; the player is having difficulties with their classes' armour limitations.
Elf Player: I'll try to pick the lock on the chest.
GM Troll: You can't - you're wearing plate armour.
Elf Player: I take my armour off, then.
GM Troll: Just so you know, it will take you four rounds to take your armour off and six rounds to put it back on. And there IS a hobbit thief in your group...
Elf Player: That's no problem. I can do most anything myself except heal.
GM Troll: *sigh* Ok, go ahead...
Elf Player: [Removes plate armour.] OK, now I'll pick the lock.
GM Troll: [rolls successfully] Hey, look at that! You actually pick the lock!
Elf Player: Now that I've picked the lock, I'm going to put my plate armour back on.
Dwarf Two: Oh, for Pete's sake...
GM Troll: Ok, that will take six rounds. [rolls] Oooohhhh... not good. Just as the elf is about half way through putting his armour back on [rolls], three orcs round the corner 30' away. [rolls] Neither side is surprised. They see you and charge, screaming, "Kill the intruders!" [rolls] Someone please roll initiative for the group.
Elf Player: [rolls] A six! I cast sleep on the orcs.
GM Troll: You can't. You're still partially in plate armour. It will take you two rounds to remove it or three rounds to finish putting it on.