I instantly loved my Petalil Lilil as soon as the NPC traded her to me. I never knew that she would evolve into such a strong and beautiful Lilligant though! It was a pleasant surprise.
As for Meloetta I never knew she was a legendary (at FIRST), but I like her too much to not use her in my team. >_< I don't use Pokemon because they are powerful though, I use ones that I like (their personality and design).