At a minimum, I carry sunscreen, a small air compressor, tire plugging kit and water. Also, a few basic hand tools and an air gauge.

 

A jump pack for jump starting a weak battery, either yours or someone else.
I even keep a small set of mc jumper cables in case the jump pack does not work.
Keep one in the boat, too.

 

Rain Gear, Stop and Go tire plugger with small compressor, tools, volt meter, Light Jacket and the list goes on until both saddlebags are full.

 

Here are a couple of extra things I carry in my bags. Extra Key Fob Batteries (2032 for me), spare seat fender nut, c-clip and screw. Spare crank position sensor and a spare shifter arm. I tend to go on some long ride in middle of no where and each one of these things I added just in case after needing all of these at one point or another.

 

pretty much what others have said. Packable rain gear, tools, some bungie/tie wraps, kickstand plate for soft surfaces, and various odds and ends depending on where i'm heading to.

 

Rain Gear, Fob battery (need to pick up a new one, just changed it), air pressure gauge, cargo net, ratchet strap, med kit, tool kit, lotion and a Playboy.

 

Leatherman tool, rain gear, extra FOB batteries at a minimum. After that, tire plugs with compressor, extra fuses, lithium jump battery, eZ Pass for toll roads, LED flashlight & more tools.
And I do not have OCD, but I do like the side bag organizers. The tour pack organizer, I don't use as much, so I'd skip that one. And for easy carry of clothes, one saddlebag carry insert. Looks better going into a hotel than all my stuff in a garbage bag.

 

A couple of maps. Useful for mapping out a ride or adventure. Take a look at the Butler maps.

 

Rain gear tie down straps or bungie cords tire plugs along with a assortment basic tools for a minor breakdowns. Cleaner spray and rags to wipe down when needed

 

I have the the soft bag inserts for the hard bags and the organizers, love them both for trips. I hate having stuff rolling around making noise. The soft bag inserts are nice because you can pack and just remove from the whole bag and take them inside to where you're staying. The organizers are nice for the smaller stuff, sunscreen, extra glasses, keys, and what not.

As far as what I bring on rides or trips, that would be rain gear, extra jacket, gloves, tool kit, sunscreen, and some terry cloth towels.

Ride safe!