why don't you like it? I find that to be the most useful Gmail feature there is.
Because sometimes they'd group things together in conversations that aren't conversations, for example, I wanted my online shopping email account to be a Gmail account. With this, there are NO conversations but sometimes they'd group somethings as conversations but not other things. I never could figure out why some things that weren't conversations were grouped as them but other, similar things, that also weren't conversations, weren't.
I'm sure there are other instances where you have a collection of email that aren't in any way conversational but that was the reason for me.
I always wanted it as an option because there are times, for general emailing, I'd guess, where this feature makes sense so I didn't want it eliminated completely.