We will discuss a result, joint with Deng, Ionescu, and Pausader, about global regularity for the full 3d water waves problem in the presence of gravity and surface tension.  In this problem there are difficulties that have not been present in any other water waves model treated so far (nor in other quasilinear evolution equations).  The main issue is the slow decay of linear waves with the simultaneous presence of large sets of coherent interactions.  We will discuss prior works on this and related models, explain the new difficulties, and give some details of the proof.