For a moment I thought Wanko was naked inside the box
Scratch that, it turns out she was and I wasn't just mis-seeing things, that must have been an awkward request to give to her coworkers
I was going to ask if I was seeing things or if Wanko was naked other than the cape and bows tied in strategic locations... at least covering her breasts... with her coworkers there to help her set up the surprise... That's asking a whole lot of your coworkers! I don't think I could ever even THINK of asking my coworkers to help me with something like that!
I'm also guessing that Elly's work meeting going long, probably because of the birthday celebration at the meeting, nice gesture that it was, taking up time that would have been dedicated to ... you know ... actual WORK ... lead to Wanko being naked and cold in the box for a bit longer than she anticipated and, thus, needing to go to the bathroom IMMEDIATELY after popping out to surprise Elly.
And Ataru certainly has it bad. It's clear that she'd do anything for Elly, but I don't think the conversation in the car on the way home reflects well on her since she pretty much was sowing seeds of discontent and trying to add to Elly's already low mood by suggesting that their relationship was headed toward stagnation. Speaking as someone who, despite being at an age where birthdays don't really matter that much, had one a few years back where my very young daughter, quite late in the day, asked me when my birthday was, knowing it was coming soon and I had to tell her while fighting back tears that it was today and then tell her that "no... nobody remembered it" when she asked, it's not something that needs to have extra angst added to.