Persistence is often the key to success: true.
Perseverance and determination are elements that contribute to the achievement of every important goal: true.
Nevertheless we humans have a tendency to interpret every act of purposefulness with something else: stubbornness.

Stubbornness is the force that drives us to be self-righteous and
100% convinced of something even when we are completely and objectively
wrong.
Diligence and fortitude are essential for achievement and great
performance but when insistence is taking the place of persistence one
can end up performing the same action repeatedly after failure. When
studying effective people you can always find a blend of determination
and flexibility at the core of their decision-making engine. They
would never stubbornly fixate on one task or problem without trying
different approaches; otherwise this will stop them from attaining the
desired end.

Often
times, a detour or an alternative approach around the insurmountable
wall in front is the only way to get to where you want to go, so that
the aim persistently remains while you are dealing with the problems
that may crop up along the path.
The real stoppage arises when one is so fixated on a present problem
to the point that the original aim is lost and the person falls into
the qualms and worries of the hindering situation.
Whichever way you choose to travel, do so with confidence, drive,
and resolution. But when faced with an insuperable and unchanging
obstacle, don’t try to continue as you have so far banging with
frustration against it.
Keep the goal persistently in your mind while trying to creatively solve the problems in the way.