If you give a professor a key...

If you give a professor your lab key after class, she’ll remember she forgot to turn any of them in.
So after picking the rest up from her office, she’ll bring them to the storeroom.
On the way she’ll spy her overnight cultures in the growth chamber.
After dropping off the keys, she’ll get the cultures and bring them to her lab.
She’ll discover thetabletop centrifuge is missing.
After hunting down the centrifuge in someone else’s teaching lab, she’ll carry it back to her lab.
The inserts are missing, so she’ll search for them.
She finds them in the cold room, and also sees a plate from one of her students.
She’s curious to see if the Blue Fluorescent Protein really fluoresces blue, so she’ll shine the UV light on them. Nothing.
Upon returning to the lab, she discovers she forgot the inserts…back to the light box.
At the lightbox, she also spies a catalog, and remembers she needs to order some things for summer research.
After starting the centrifuge, she sits down at the computer to order some supplies.
Students come to ask about their grades. One of them says how much they enjoyed the blue fluorescent protein project…and she’ll remember the samples in the centrifuge.
She’ll go to the lab and discover her colleague locked it.
She’ll discover she’s wearing the evil “no pocket” pants and can’t find her keys.
So chances are, she’ll ask you for a key.

This is why simple things seem to take forever some days...