To begin with, I want to emphasize how important it is to
recognize that Hetalia is not a series that believes in permanent grudges. Regardless of
the betrayals that occur in the manga, the grudges that the nations bear rarely
if ever remain.

This doesn’t go to say that grudges can’t last for a long
time, because they do and for good reasons. What I’m getting at here is that
while the nations are cultural personifications – representing their citizens,
not just the government – they’re also people just like you and me.

How the nations associate
with each other is influenced by their political relations. On the other hand,
to say that, because of these rocky political relations, the nations in
question inevitably hate each other is a shallow way of understanding things.

Their pasts together extend beyond their present situation. They’ve
lived for several lifetimes and have their own memories and experiences; there are
other factors to take into account that influence how they view each other on a personal level. To view and associate are two
very different things that are wrongfully equated together in the fandom.

I say this because you’ll see moments where enemy nations
drop their political masks and treat each other as friends.

Ex: After being stranded on Seychelles during WW2, Italy invites
France to his side of the island and asks not to pick a fight. Italy still
fondly refers to France as Big Brother, a title that originated from their
childhood spent together in Rome’s house.

Ex: When he occupies Rome, rather than treating the Italy
brothers with hostility, America politely asks them to make him authentic Italian
cuisine.

Ex: Italy excitedly greets Austria after his annexation,
despite having recently fought him in WW1.

What this post will explore is how grudges held by the nations
subside with time.

That said, let’s go over some examples.

America and England: 

Of course, I’ll get the most obvious one out of the way
first. America’s declaration of independence was experienced as a personal betrayal to England.

Ex: He’s noted to have had a stormy temper in the decades
following America’s independence. [x]

Ex: While it’s not explicitly stated, it’s alluded that
England is talking about America when he claims to have suffered from 100 years
of heartbreak.

Of more importance is that aside from their volatile political
relations, America still demands to see England when he hears that the latter’s
fallen ill as a result of the war.

Notice how distressed and panicked America is here. He even
tries to force his way into the house, despite being barred entry by
Canada. Again, the personal triumphs over the political.

As mentioned, with time, a lot of this anger and resentment disappears.

Ex: England takes the leap and attends America’s centennial
celebration.

Ex: The two are now able to tease each other void of any
spite.

Belgium and Netherlands:

There’s a rocky period in their relationship after Netherlands attempted to unify them into one Kingdom. Belgium declares her
independence instead.

We learn from his bunny how upsetting this “fight” was for
him. He copes by constantly keeping busy.

China and Japan:

This one is definitely the most difficult betrayal to
digest. It’s easily the most brutal scene depicted in the manga.

Japan stabs an unsuspecting China in the back during WW2.
What I want to place particular emphasis on is the fact that even though China
knew that their political relations were tense, he still personally trusted Japan, even as the katana was pulled out.

Additionally, notice how Japan’s face goes blank before he
stabs China. To me, this appears that he’s emotionally removed himself from the
situation.

In the aftermath of this betrayal, we see China drunkenly
crying as he realizes how war has changed Japan. Russia’s response to this is
crucial. 

Nations don’t remain as enemies
forever.

It’s the good memories that last.

Even though China developed a grudge against Japan, it doesn’t
last.

Ex: In a more recent strip, China attempts to strengthen his
diplomatic ties with Japan.

Following the abolition of their empire, Lithuania falls
under Russian control. As Lithuania’s forcefully dragged away, Poland doesn’t
answer Lithuania’s pleas for help and instead laughs at his facial expression.

Because of all the fond moments they shared together,
Lithuania resents Poland for this, but he doesn’t hate him. 

If he did, then he
wouldn’t have warned Poland of Russia’s plan to invade him in WW2.

All in all, the point to take away from this is that while
hatred exists in the manga, it doesn’t persist. Political relations may influence
the nations, but in no way does it define them in whole.