Who says all classical concerts need to be hours-long, gussied-up affairs? With Untuxed, Seattle Symphony is keeping things casual and brief – with no intermission and a total running time of just over an hour – for a fun and enriching concert of classic works by Mendelssohn and Beethoven at beautiful Benaroya Hall. Mendelssohn’s String Quartet No. 6, the composer’s last major work, delivers wave after wave of intense emotion, from passion and anguish to tenderness and grace. This masterful music inspires total focus and presence – just like Beethoven’s Symphony No. 4, which sweeps you from tense foreboding to sweet joy and all the way to rowdy humor by its climactic end.