Why were 9 Volt and 18 Volt enemies in DIY again?

[CM30]

I never understood this. Did they ever explain why they seemingly didn't get along, worked at different companies and in the latter's story, actually fought each other?



Any ideas?

 

[ShyGuyXXL]

You mean in the little cutscene there?

I see it more as a friendly rivalry.

 

[Exeggutor]

They probably played Mario Party.