Has anyone got any suggestions as to accessible string quartet or other chamber music that

a) sounds so nice that you would actually want to play it

AND b) surprises you by the fact that you can play it

My suggestions are:

(i) Borodin SQ no 2 in D 3rd Movt "Nocturne".
(ii) Dvorak American quartet - final movement.
(iii) Haydn Lark quartet - finale vivace.
(iv) Frank Bridge- 3 pieces for string quartet- listed as piece no 2 but recorded as piece no 3 - the jolly seasidy one.
(v) Shostakovich SQ no 1- each of the movements 1,2 and 4 is wonderful in its own right, and since the third movement is pretty good, it seems a shame to chop it up at all.
(vi) Bach Mass in B minor "Domine Deus"
(vii) Mozart clarinet quintet 1st movt.