Make. Fucking. Backups...

I had to find a MailChimp sync plugin for a webshop and thought I found a good one that synced one way (webshop to MailChimp).

I figured, meh, what could go wrong? So I installed it, ran it...and somehow lost around 4000 mailinglist receipients because they were not in the webshop.

Turns out it adds the registered users in the webshop, but also removes entries that are not! Needless to say, I had some explaining to do and was only able to recover about 3000 addresses from a previously sent campaign.

Customer was not happy, neither was my boss, very important lesson learned...