I dont really remember doing as much of this in my school days even in the classes I didnt like but lets see how many you recognise.
Although officially I have to teach a 50 minute lesson, I often find that actually I sometimes teach as little as 10 minutes a lesson or on a good day about 35 minutes.
This wastage time is made up of the following - now remember, I have to collect the kids from their classroom and take them to my classroom.
In the homeroom
Writing down homework from the board from the previous class
Playing in the lineup
Going to the toilet
Dropping notebooks / pencilcases on the way out
Tieing shoelaces ( that do or dont need it )
Forgetting something and going back into the class to get it
In my classroom or on the way
Insisting that the broken pencil stub is the only one that they can write with as it is lucky
Chatting with friends
Insisting bringing everything from their homeroom they could possibly need for the class and then not find the thing they actually need or take10 minutes to find it in in the bag
Ignoring you - even from 1 yard away. It falls into different varients - the total ignoring or the ( this is the most annoying to me) saying yes to your instruction then immediately going back to whatever they were doing before you interrupted them.
Hiding under the desk
Hiding in a cupboard
Hiding under the chair
Crawling on the floor
Pushing the book / notebook / pencil / ruler onto the floor to retrieve it
Sharpening the pencil so that a brand new pencil instantly becomes 1 inch long - I hid all the electric pencil sharpeners in the room the moment I saw them.
Not noticing that I am walking away with the front of the class so 20 kids can be spread out over 3 floors until they notice I am not there and of course run at full speed knocking over everything and anyone or falling over. Or not caring and just wandering along in their own good time ( more likely )Needing 4 of your friends to help you sharpen your pencil / open your book / tie your shoelace
Making "funny" comments when you are trying to teach so getting me to tell you off and stopping me teaching ( it depends on my mood if I ignore them or not ! ) Other ones in this variety are - playing the desk / pencil case / the head in front as a drum with a ruler / pencil
Playing with the pencilcase and its built in game of pinball / football / mini whiteboard
Looking at another page in the book
Drawing in the notebook
etc etc etc