on a more serious side this is the list I carry with me whenever I go outside:

- Pump (hate CO2, mine is a Topeak Road Morph G - has a gauge so you can pump to whatever PSI you need, goes up to 160 PSI, the foot pad is awesome, light and small and works with Presta/ Schrader/ Dunlop valves).
- Lock (I use a mid security u-lock, my city doesn't need something like the NY Fahgettaboudit)
- Oh noes kit (tire lever, patch kit, 1 extra tube)
- Multi tool (insert fith element joke here, mine is a Topeak Alien II)
- Small Adjustable Wrench, this way you can carry just one wrench to service your bike when needed