It is always best to keep smashes and drops shots straight or to the centre. When you are smashing from a corner, these are normally your best choice, because they have the shortest distance to travel and less time your opponents have to react, and the faster the shuttlecock will be travelling when it reaches them. you can add an additional choice of smashing towards the outside edge of the court, or aim directly at the defender.
In general, many players prefer cross court drops and smashes, as they think they play advanced strokes. This shows a fundamental lack of positional understanding. one should usually avoid playing these, because they have the longest flying distance, slower than your straight smash because the shuttlecock travels farther across court, it takes longer to reach the same distance from the net and your opponent will have more time to react
A much experienced player will be standing closer to the net than his partner covering the straight angle. Because he can play much more effective counter-attacking shots.
If you play a cross court smash, more chances ar ethat your opponents will be ready for a straight reply or even a lift can cause you problems. The best stroke to deceive your opponent here is to play a straight drive.
Of course, there are occasions when a cross court smash is a good shot when your opponents are forced to be out of position. If they are covering the court well, you should probably avoid smashing cross court.
More experienced players even make it up a tactic move to smash straight to the defender. Because no one can play a goodreply when hit close to one’s body.