I think proper seat selection can have an influence on your ROI. You should sit to the right of people who are too tight/don't defend their blinds. But if they often fold their small blind whent he blinds are big, you might want to sit to their left. I'd like to have loose players to my right, and I'm not sure where I want to sitin relation to 2+2ers (tight early, aggressive late, etc.). Because they don't only push all the time in late game, but they also call me with less-than-good hands, when I'm in a spot where I'm pushing any two. Because of this my push range is tighter than you'd expect against them.