I like to imagine them frienemies and only act friendly "on camera".
Plus when they have to work together against common foe (for example against Bowser + Eggman combo in 3DS London 2012 Story Mode).
![](https://pbs.twimg.com/media/E_hwkV5XEAQcqgL?format=jpg&name=small)
![](https://pbs.twimg.com/media/F07P4J1aIAA-qAk?format=jpg&name=small)
Kinda like Goku and Vegeta when they have to beat Freeza, Cell, Buu, etc.
![](https://media.tenor.com/vM0BXi-C2BYAAAAC/goku-vegeta.gif)