The left-hander's brain is OK with using the standard QWERTY layout for typing but those doing a lot of spreadsheet work will appreciate that their left hand is more suited to keying the numbers. Forcing the use of the right hand when using the number and directional keypads can lead to discomfort and pain which can become a big problem long term for employers and employees alike. Switch over to a left-handed keyboard and your natural abilities will shine through with increased speed and accuracy!