"Dear Blizzard, Thank you for making Ana" was a post made by /u/tsunderella_x on the Overwatch subreddit on 24/7/2016 where she gave her gratitude to blizzard for adding a motherly character in to the game. The post quickly raised to the front page, where it quickly spawn parodies like "Dear Blizzard, Thank you for making Reaper" where the creatoer thanked blizzard for making a edgy character like himselv or "Dear Blizzard, Thank you for making Reinhardt" thanking VBlizzard for making a knight just like himself.

Original post:
It's no secret that Overwatch has a very diverse cast of characters, but Ana in particular really shocked me. I'm a mother myself, and although I am not quite as old as Ana (my little baby boy is still in diapers) I really appreciate the attention Ana was given as a back line support for her team.
It's really stupid, I know, but the fact that I actually play the team mom, pushing payloads, having my team walk up to me and ask for healing b4 charging back into the fray, and boosting the moral by giving out nano boosts when they feel confident in their ult. It's just really good design. You really did make Ana mechanically a mother for her whole team. So again, thanks. You did a really great job with her.