Piano
An instrument that looks like it will be fun to start playing, but is extremely tideous and difficult, and therefore seen as boring by many. However, when you become an advanced pianist, you will look at the instrument as God's greatest gift to humanity.
Guy A: ugh, I wish I never wasted all of that money on piano lesson. It has to be the most boring instrument ever! Three years with this piece of crap they call an instrument!
Guy B: I've played it for 17 years, it's the best thing that ever has happened to humanity.
Guy B: I've played it for 17 years, it's the best thing that ever has happened to humanity.
Get the Piano mug.