Credit goes to YEYP

Here we see Seth at a cafe where he was known to have a very high tolerance to sour, more specifically Nomel Berry Cider. Seth was so eimotionally that he won many juice bar bets since he downed so many sour beverages. When asked why, he goes by his motto "emotions slow you down" even when Kroko forced him to do hits for him, he would usually drink some sour beverages. Even with his emotional recovery, he still has a very high tolerance to sour as it's the only thing he'll drink.
The second will probably be spicy, but he prefers sour as he enjoys seeing others be in utter shock at downing or even eating a whole Nomel berry and not even flinching. He still drinks to even when resting on the air continent, his mother tried getting him to try others, but he found them distasteful, so she makes to stock up on sour berries as their the only types of berries he'll eat. Like Mercury and Crescent, most juice bars have a drink named after him "Sour Leaves" which is a variety of sour berries and even a few sour berry seeds with an edible leaf in it.

Seth is starting to enjoy teh fact that others tease him for wearing pink, but if it's someone he hates, he's won't hesitate to turn his sword on them. Many often took juice bar bets that Seth always won because he has a very high tolerance to pain, he also has a very high tolerance to sour, Deliah makes sure she stocks up on sour berries so that Seth can have his specialty drink. She accepted that Seth won't try anything else, but many juice bars and cafe located on the island do miss Seth as no one has a tolerance for sour like he did.

Seth Belongs to Me
Grovyel belongs to Game Freak