system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why the USSR and the USA didn't remain allies

Why was it so sudden that after WWII ended the two super powers were at each others' throats, why couldn't they have continued being close allies?
gpt
They weren't exactly close allies in WWII either, just reluctant bedfellows, due to a common enemy.

In fact, the beginnings of cold war scheming, on both sides, had already started before WWII ended.