I have to disagree with some points here. I don't find Neelix that obnoxious.
Annoying sometimes, yes. But not obnoxious.
I must also state that I do find Neelix one of the best characters Star Trek ever have come up with!
I guess that some people who are reading this are shaking their heads now. "Has he really gone off the rails totally now?" some people might think. Or "Has this something to do with Kes?"
But I have not gone off the rails and it has almost nothing to do with Kes.
As I see it, Neelix was actually the most "normal" character in Star Trek. An example of a poor guy who has gone through a terrible trauma and is trying desperately to move on and live despite that.
As I've wrote before in another post,
he character had more depth than I think many people realize.
His whole "comical" and somewhat annoying behavior was actually a result of a terrible trauma in which he lost his whole family. To cope with that horrible experience, he took on his duty to help, to cheer people up and to be as useful as possible for the Voyager crew.
OK, he was overdoing a lot of things which gave the opposite result of what he wanted and he screwed up his relationship with Kes. But that was also a result of the trauma which affected him deeply. He was a very complex person.
If Voyager had had a counselor, that person would have had to spend a lot of time with Neelix because the poor guy really did have some "issues".
Neelix desperately tried to "fit in". Obviously he did know deep down inside that his skills were limited so he tried to compensate for that with a lot of ideas and whims, like his self-made role as "Morale Officer", how he became almost obsessed with the idea of being an "investigating journalist", the Talaxian resort he created at the holodek (which Harry and Tom totally changed) and his bragging about his skills as guide while his knowledge about the Delta Quadrant was limited. That was also one of the reasons why he and Kes started to drift apart as soon as they came on board Voyager.
Kes found a purpose for her life on the ship. A new reality, new people, the Hydroponics Bay, her work in sickbay and an ardent will to learn and explore.
Neelix on the other hand found his skills rather limited and therefore did all he could to get attention, like "look at me, I'm good, see what I can accomplish. His jealousy over Kes probably had something to do about being jealous of how good Kes did adapt to the new life and become an useful member of the crew while he did find himself limited. Not to mention that his control over Kes started to vanish as soon as they joined the Voyager crew.
I also think that he still had bad memories about what happened to his family so in an attempt to keep those feelings away he tried to be positive, cheerful and tried to cheer up everyone on the ship, like "I want happiness around me so smile!".
Of corse he over-did almost everything he was involved in. His pestering of Tuvok was actually horrible and annoying (but fun to watch) and I can understand Tuvok's frustration over those current attacks from Neelix. But his intentions were good.
Just because of all this, I find Neelix interesting, likeable and a good written character (except for how they dumped him at the end, a stupid decision from the writers). I think Neelix is the only character ever i've found both likeable and somewhat annoying at the same time.