You're a burglar, but....

[I like Skol]

Door knobs

Only the ones on the inside of the rooms, obviously

 

[davelincs]

The out of date tinned food ,and sauces

 

[Archie_tect]

All the taps in the house.

The fuse from the spur socket to the boiler.

 

[Amanda P]

All the soap.

Or if I’m feeling particularly devious, break in repeatedly (but undetectably) and keep moving the soap from the shower to the bathroom sink, where it’s just out of reach for anyone using the shower.

 

[I like Skol]

Perhaps we should focus on something cycling related?

Ooh, I've got it! One bolt out of each Shimano SPD cleat.

 

[Archie_tect]

The labels from tins.

 

[flake99please]

The letterbox. Enjoy the breeze.

 

[postman]

The little notebook with all the passwords in.

 

[Archie_tect]

Pete, this is stopping me from working....

The little wheel in everyone's mouses [mice?]

 

[Amanda P]

All of one person’s underwear, so they’ll have to borrow someone else’s.

 

[LCpl Boiled Egg]

The cable that connects the wi-fi router to the outside world whilst leaving it powered on.

Edit: Although that's not a mild inconvenience for most people...

 

[LCpl Boiled Egg]

The dangly light pulls from the bathrooms.

 

[Amanda P]

Sink plugs.

 

[DCLane]

All of the mobile phone charger cables.

 

[si_c]

The drain plug for the kitchen sink.

Edit: Beaten to that one by @Amanda P