Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Just now, I was at 1408, then, suddenly, I saw that it had dropped down to 1402 with no notice in the reputation tab. Why did this happen?
Because you deleted this answer.
It had one upvote (+10 rep) and two downvotes (-4 rep), so deleting it cost you 6 rep.