I agree , that a firm handshake is the best first impression that you give to someone.Limp wristed ,dishrag shakes are considered to be lame imho.
Yeah some dudes over do it and squeeze the hell outta your hand or grab you by the fingers and snap em like twigs.Generally these peeps are overbearing bullies.
Back in the day some guys shook by interlocking thumbs with facing palms with forearms at 45 degrees.This was considered a cool shake at the time.
But the old fashioned way is the best.