any champion can be good if played right
Ah, I'd consider Singed one of my mains, so I just get a little offended when anyone puts him in the category of "trash"
Singed is a really good agitator for pissing people off. Someone doesn't know your kit? Free first blood for you. Someone does and plays safe? Free farm for you. They come to gank you? Flip their jungler, ghost ult and zig zag away so they chase through poison.
Also, if you're not bringing ignite ghost on singed, you're playing him wrong. If you have any questions on Singed, I'd be glad to share some of my knowledge.