All Cosmos ever wanted was to see his friends. His Tech Spec bio states that he gets lonely in outer space, being one of the Autobots' first lines of defence against the Decepticons. He realises that his job is extremely important, but as a social creature, it doesn't make it easy for him. I always felt for Cosmos as a child, it seemed so unfair that he'd feel that way. But while the Decepticon Blast Off (who was in the same boat as Cosmos; spacebound and lonely) covered up his feelings by being overly aloof, Cosmos goofs off, landing in people's backyards and scaring them a bit. Good fun, for Cosmos at least.
In the cartoon, his voice always sounded slightly Hispanic to me; it wasn't until years later that I found out that this was actually supposed to be an impersonation of Peter Lorre, something I'm still not convinced by. If it IS supposed to be that, it's not a great impression. I can do better, and I always end up sounding Chinese, apparently.
Cosmos may be a lonely guy. But he's loved in the fandom, for both his fictional portrayals and his toy. There are third party versions of him out there; seeing as Hasbro seem to be the ones giving him little to no love these days, maybe it's their turn to make the little guy even more awesome than he already is.