When Jerry Seinfeld and Larry David pitched a "show about nothing" to Seinfeld off the ground.
The main character is a replica of the real Jerry, with the other three friends being unofficially based on people the showrunners knew in real life. Jerry plays a keystone role in the show: he is the rock around which the other characters play out their lives. As sensible as he seems, though, he acted in some ways and did some things that would not be considered normal today.
Unfair Expectations Of His Friends
Jerry and George have been friends since high school, ever since the latter collapsed on top of him while struggling to climb a gym rope. However, he expects George to be around all the time, even if he might not return the favor. In fact, Jerry has gone into spirals of sadness whenever he feels a threat looming over his friendships.
In The Invitations, George's imminent wedding is a source of frustration for Jerry, who whines about the marriage breaking the group apart. When Kramer and Elaine can't spare time for him due to their own strange adventures, he exclaims that "the whole system's breaking down!" Maybe he should have given them some space to do their own thing from the outset.
The Deal
Although Elaine has dated Jerry in the past, their relationship in the show is entirely platonic. Well, almost. During the events of "The Deal", the pair decide to try out being friends with benefits. Unfortunately, this doesn't pan out as planned and they start acting like an old married couple soon enough.
However, with the advent of the internet and dating apps, this sort of relationship would have never emerged in the first place, not with cold-hearted ghosting being one of the first possible choices available.
Obsession With Hygiene
Jerry's compulsiveness towards maintaining a germ-free environment borders on delusion. Setting aside the fact that nobody questions his behavior or suggests that he get some help, the show plays his disorder for laughs. In one episode, his girlfriend compares him to Hitler for his insistent demands.
In "The Pothole", Jerry spends the episode freaking out because Jenna put one of his bathroom items in the toilet as revenge, so he discards every object in the vicinity. Later, he is relieved that it was in fact the toilet brush, but the subsequent explosion of toilet water all over her (due to George's meddling) causes him to instantly dump her.
Ridiculous Financial Decisions
In "The Stock Tip", George coaxes Jerry into purchasing $2,500 worth of stocks in a rising company. The shares tank over several days and Jerry worries about losing everything, so he sells them for a huge loss. It is expectedly upsetting for him to find out that George has made a considerable profit because he waited long enough.
In "The Cadillac", Jerry throws his money around again: when his parents sell the Cadillac Fleetwood he buys them (to avoid the resultant embezzlement scandal), he repurchases the car out of spite. To provide some context, it cost him nearly $40,000, but Jerry spends another $20,000 to get it back. Imagine living in NYC and having money to buy a car, let alone do this nonsense.
What He Does To His Family
Jerry might love his parents, but his feelings rarely extend to his extended family, for instance when he (possibly) accidentally kills one of his older relatives in "The Pony Remark". With Elaine's encouragement, Jerry scoffs at ponies, further stating his abject hatred for "any kid who even had a pony!"
Unfortunately, once-a-child-with-a-pony Manya is upset by his remark, even though he doesn't mean it. She dies later that week, and Jerry is left feeling haunted by her vengeful spirit. He should have tried being more considerate from then on, but it's back to business immediately.
The Reasons Behind His Break-Ups
Jerry seems incapable of accepting that any woman could actually love him, going so far as to dump a number of amazing partners for the silliest reasons. Some of these terrible reasons include: eating peas off a plate single file, having "man hands", not getting a massage (her being a masseuse), for being way too similar to himself, and, worst of all, for having been dumped by Newman in the past.
He has been dumped on equally ridiculous bases — from knocking someone out to access their toys to refusing to eat mutton that is lovingly made for him. How he continues to find more women to mistreat remains a mystery.
The Hero-Worship Of Superman
The entirety of apartment 5A is a shrine to the Man of Steel. There is the statue and the refrigerator magnet, but there are also the ceaseless references to Superman in a number of episodes. Although superhero fandoms are more powerful than ever, it is still a pursuit of youth, not for a man in his mid-30s (and later, his 40s.)
In fact, this even escaped the universal limits of the show with the release of the American Express ads, The Adventures of Seinfeld & Superman (the latter character voiced by the same actor who plays Elaine's ex, David Puddy). Seinfeld shows that meta-narratives make for some excellent comedy. Probably not this one, though.
His Temporary Engagement To Elaine
In "The Serenity Now", Jerry is told that he lets people walk all over him, with Patty further commenting that she has never seen him "get mad." He figures it out, alright, exploding into a conflicting puddle of emotions, including anger, but also love and comion.
In this state, he asks Elaine to marry him, and she leaves in total shock without giving an answer. George comes into the picture at this point: his own emotional explosion converts Jerry back into his usual state. When Elaine returns to accept his proposal, he counters with a callous "I tell ya, I don't see it happening." Typical.
Total Lack Of Seriousness
Whenever his friends come to him with some tale of woe, the most they receive is a shrug and an empty "That's a shame." Jerry doesn't know how to deal with his emotions (as seen above) but this inability seems to wrap around his entire personality. For instance, he doesn't really empathize with George over Susan's death, but neither did Elaine, or George, for that matter.
Jerry tends to make light of most things in his life, probably because his career choice cannot afford any other reaction to the world. This attitude is not very pleasant, however, especially for the people that he seems to ignore or even mock for their suffering.
Using Friends To Build His Career
Jerry has never really been invested in the nonsensical shenanigans his friends get themselves into, although he is always available to lend a listening ear.
While his advice can be sage on occasion, the main reason he keeps in touch with Elaine, George, and unworthy friend indeed.