In some episodes Jerry and Nibbles act like Rick and Ginger’s home is their home too and eat all the food they want, while ignoring the fact that they are mice not allowed there and invading their home. However the episode “In The Beginning”, shows that the house was originally lived in by Jerry first before Rick and Ginger moved in there and they tried to get Jerry out (Which is why Rick bought Tom as well). So to it makes sense for Jerry to act like this, sense of you really think about it to Jerry’s perspective, it was actually HIS home first and THEY are the invaders (Even if technically they legally bought the home fair and square).
While it can be jarring to see Spike being an smug jerk later on in the show, rewatching the first season and the episode "In The Beginning" can provide some insight on how this happened. "In The Beginning" shows an much nicer Spike who only got angry at Tom when his antics went too far showing that he wasn't always like how he was later on. Season one meanwhile had episodes like "Spike Gets Skooled [sic]" and "No Pets Allowed" where no matter what he did, Spike would lose even if he was just trying to enjoy himself. So when you think about it, Spike only became the jerk he is because he's lost his temper with the duo and the antics.
