Dynamical interactions that take place between objects in dense stellar systems lead to frequent formation of exotic stellar objects,unusual binaries,and systems of higher multiplicity.They are most important for the formation of binaries with neutron stars and black holes,and especially for mass-transferring system – low mass X-ray binaries.Those are not only formed 100 times more efficiently than in the field,but also have a puzzling dependence on metallicity.The neutron stars and black holes have different favored paths to become luminous in X-ray,and triples formation is especially important for black holes.I will also discuss how stellar evolution can affect ostensibly purely dynamical formation,producing observed metallicity dependence for low-mass X-ray binaries.