Piano Forum

I'm surprised people still haven't identified it.

Just to clarify, pianoplayerstar was being sarcastic when he was it was 'esoteric'.  The overall tune is quite famous even if the brief excerpt posted in the thread isn't. 
 
Five more hints:

1.  If pps had posted the bass, more would have figured it out. 

2. The piece, to the best of my knowledge, isn't one that has a moniker.  The name of the genre with it's opus number and key signature (and the composer) are usually how people would refer to it. 

3.  In all likelihood, it's in the running for the piece that firsts pops in your mind when you name the genre, even if you didn't name the composer. 

4. There are two other works in the opus.  If you don't get it after this hint and some trivial math, you don't recognize the work with its opus number which I find quite unlikely given how famous the work is (but still possible?) or you're undergoing a brainfart.

5. You likely have it in your sheet music/books.  You don't even have to have a book that contains all the other works in the genre by the composer to have it.  It's one of the pieces that's always put in generic big-book collections of "classical music". 

One more clarification.  It's famous enough that people should recognize the tune despite not having a moniker, but because it doesn't have one or a distinct title beyond its genre, it makes it hard for the general public to "name" it.  Only musicians who are used to referring to opus numbers would make a habit of "storing" the name in their minds.