Take a look around society. We see a lot of weak people. Mentally, people allow the smallest of circumstances to get ahold of them and dictate their actions. Emotionally, they their emotions to get the better of them and, physically, people are unhealthy.
If you have any hope of becoming the man you are meant to be, you are going to need to learn to develop strength in each of those areas. And, the only way to get physically, mentally, and emotionally, is to embrace discomfort.