against the grain

Short definition from Wiktionary

Prepositional phrase

1. 1
   Preventing a smooth, level surface from being formed by raising the nap of the wood or causing larger splinters to form ahead of the cutting tool below the cutting surface.
2. 2
   Contrary to what is expected; especially, of behavior different from what society expects.
3. 3
   Unwillingly, reluctantly; contrary to one's nature.
4. 4
   Used other than figuratively or idiomatically: see against, the, grain.