Why become a sissy?

What? Ii isn't done on purpose. People don't just wake up one day and say oh I think I will be a sissy. There are way more factors such as environment that you were raised in.

People become sissies because it is how they enjoy being.

Yes, you don't just become one . It is either there is or it isn't . As a rule you know you are different from the time you were young . Like on Thnaksgiving the men are watching football and you feel better helping the ladies in the kitchen. Sissies are usually born, not made

New Answer:

It depends on what you mean by "sissy." Given the category, I assume you mean it in the fetish sense. I became a sissy for a number of reasons, both conscious and compulsive.

• Being a sissy relieves me of all kinds of performance anxiety and pressure to succeed. Those who know me to be a sissy do not expect me to win the affections of females, or to be in command or take charge in confrontational situations, or to achieve executive status at work. The things that are expected of me - obedience, sufferance, etc. - are of a very different nature and less stressful for me.
• Being a sissy is also a turn-on for me. Fetish is eroticized fear and the stress I felt/feel to achieve and control in various ways, to make the grade and "be a man," have been eroticized for me so that being humiliated, demoted, and mocked for my implied inadequacy is very stimulating for me sexually.
• In particular, I personally have always feared women and their sexuality. Being more "womanly," and at the same time being relieved of any need to try to master her by my surrender, and of any expectations she might have of me, makes me feel more comfortable, secure, and calm.

There is a lot of baggage in gender roles and expectations. Surrendering the privileges and pretensions of the role allows me to surrender the burden of having to try to meet those expectations (which are impossibly high for a perfectionist like me) as well as the guilt of failure. I can instead embrace my shame and get a sexual charge out of it.

I hope that helps.