Well said, Boomerjinks.
Otaku to me is the Japanese meaning. I've seen American anime/manga fans (which I am), and American otaku. I do not like associating with otaku, and I don't like to be labeled as one because I happen to mention that I enjoy a particular manga.
People I've met who call themselves otaku do seem socially awkward. They turn the simple act of meeting friends into coplay meets, even if the setting does not call for cosplay. They are willing to ruin their costumes and wigs at a waterpark simply to see people from NDK. They state the reason for this is they feel their con friends won't chastize them for wearing the costumes; if they're so comfortable around the other people shouldn't they just be themselves and wear regular clothes? And no, don't say "But they are being themselves when they wear the costumes," - wearing cosplay so much, drowning themselves in anime-related activities, perpetually wasting money on anything anime-releated (I don't mean spending a large sum of cash on a mega-rare, out of print anime you buy once, maybe twice), tying their daily life's activity to anime is just unhealthy; focusing that much on ANYTHING is unhealthy.
And yes, many otaku claim "normies" (I HATE that word - it's ignorant and disrespectful) don't understand them. I suppose I am not classified as a "normie" because I watch anime, read manga and cosplay; however, I do not approve of otaku. If a person is halfway socially adjusted, regardless of their likes and hobbies, they can see otaku are strange. Also, most otaku I know about refer to "normies" in a criticizing manner, many times insulting them in discussions written and spoken. That's just a prejudiced mentality when people (especially the otaku that claim they're nice) insult other groups of people as a whole.
And one of the most infuriating things otaku exhibit is being overly-familiar with other unsuspecting anime fans, as in body contact, personal space and personal questions. From personal experience, it seems if an anime fan attends a meet-up or convention the otakus will consider them "their own kind" and become overly-familiar way too fast, touching the person and/or asking questions that are personal, like their name and email (when I went to my first Pillow Toast meet I was approached by an otaku from the boards who asked for my name first thing. I told him my forum screen name, but he said he wanted my REAL name). If the otakus truly understood Japanese culture from all the anime they watched, they'd understand that the society emphazises politeness (any culture does) where going and glomping random people, asking for phone numbers and using "-chan"/nicknames when they barely know the person is unacceptable (if the other person approves of the action then it's okay).