Oh my goodness, I feel for you. I'm exactly the same way with the Express Panda pet (I didn't get one from my free boxes); I never fail to feel a bit envious or aggravated when I see someone zipping by with one, especially after the Poppuri Event. However, I had a chance of obtaining one myself, when the World Boxes were released for sale in Myshop some time before the event. Despite desperately wanting one even then, I wasn't desperate enough to recharge and try my (horrible, real life) luck.
There was also another time when I really wanted the Bunny Maid equips from Gacha but I wouldn't let myself recharge. I attempted Gacha for the first time with a couple of free coins, but alas. Thank goodness items can now be fused!
Currently, I'm fighting the urge to purchase Gacha coins to get the new Dorothy pet (she's one of my most favorite NPC's) and some of the Mint/Karu stuff. I've never played Gacha with real money, only with free points and coins. I'm trying to keep this up.
^ very outdated ^
For the record, I've fallen off the face of online gaming but I've missed you guys. ;~;