I used to dislike the first TMNT on NES but it has grown on me.
I should have least favorite in regards to the second game though, quality wise it's a bit better.
Put up with giant monster attacks every few years, watch Boku no Pico at least 9 times(I'm sure you have this covered already), idolize a underage cartoon girl or two(futas count, also sure you have this covered already).