What TMNT scenes/moments/Art do you find sweet or cute?
 

The boys have their moments, there's some of the scenes with April in the Fred Wolf cartoon, in the 2003 series there's the klunk scenes with Mikey, and there are Raphael's scenes with Spike (before turning into Slash) and chompy picasso in the 2012 series

I'd say the Fred Wolf art style generally gets that reaction out of me, (especially in the Valentines Card art) it's the way they smile and show their facial expressions, Toei definitely left their mark when animating that (the anime-esque look can be notable in some scenes with Donatello I've noticed).

Rex-1's moments with April were also quite sweet and in the 2012 series, the scene where Raphael helped comfort Mikey after realizing his new pal worked for Shredder.

awww, reminds me of the scene in the fred wolf cartoon where they're all in bunk beds and she reads to them