Hairs!

"A great calligrapher doesn't blame the brush!"

- Fuji (Prince of Tennis)

Yep! Totally agree! But no offense to Fuji (I love Prince of Tennis BTW), watercolor brushes requires the bristles to absorb and hold water... so a good brush set definitely helps! :D

Here are my personally loved manes...

I feel that brushes are like magical artifacts... similar to wands. They have their own consciousness wherein they decide who should wield them... like the levitation cloak... :D

Ok, enough Doctor Strange! Haha!

My mostly used brush that I feel gets the job done for most of my works is the #8 Escoda! I really love how it holds the water and the bounce when released/applied on paper. I mostly draw portraits, so no fancy brushes here yet as rounds fit the bill for me. The widest brush on the right is what I use to spread the water on paper when doing washes. Also it helps distribute the pigments well and quickly. 

I really love the big round mops as it is versatile enough to hold water for big washes at the same time produces lovely details with its pointed tip. You just need to have a good control though.

Regardless what brand, style or kind your brushes are, just make sure you know enough what works for your style. Good brushes are expected to handle any punishment you put into it. After all, the brush is the artists channel from the imaginary to the tangible. Just make sure you take good care of it. Always clean it up after use and hang it with the bristles pointing to the ground. This would help avoid the water from seeping through the wood in the handle. Happy painting!