You may have a long walk at Istanbul - and I found it not well sign posted.
Checked in on a Business Class flight IST - FRA.
'Aisle seat, please'
'No aisle seat, only window'
Get on aeroplane. Row 1, totally empty. Row 2 full. Row 3 (last row in Business) totally empty.
So I moved to 1C. The FA looked about 16 years old, and when told I was moving, shrugged and said 'OK' and brought more champagne. Incidentally, for an unannounced reason, 1.75 hours late in boarding, no refreshments in the meantime.
But there are worse airlines......Every airline occasionally gives you a bad flight for whatever reason.