All valid questions from people who don't put in road miles or spend an hour or more on a trail bike.
But I am going to cover a few things in this article that are totally relevant to people who actually do ride and will answer for those who don't ride at the same time.
First let's deal with "why wear Lycra" I prefer to call it technical clothing as the purpose is to wick moisture away from your skin. This does 2 things
- it aids in the evaportitive cooling process to keep you cool when it is hot and helps you to dry out quicker should you become drenched in sweat
- it keeps you dryer when it is cold outside, so on the other side of the coin helps to keep you warm.

But in order to fully enjoy the benefits of this magical clothing you must first be aware of how they work and how you should wear them.

If you do not think the look is flattering to your looks, WEAR THEM AS UNDERWEAR! You can wear just about any kind of clothing over the top of them (perhaps something more stylish) and these magical shorts will still function as intended.
Wear your baggy shorts over the top and no one will be the wiser,,,, except that nosy coach who cares about your comfort on the bike and will ask you what you are wearing underneath :)
These shorts are the most important and first part of cycling apparel that you should invest in. DO NOT THINK THAT A PADDED SEAT is going to make your rear end comfy. The only solution is a good pair of bike shorts.
Why is said zipper so important you ask? Because it allows you to better regulate your body temperature in both warm and cold weather. So do not be tempted to buy a jersey with a partial zipper as you will limit your ability to stay cool, dry and warm all at the same time. (not to women, sports bras are a good idea to take full advantage of this zipper vent)
The second thing about cycling jerseys is the tech material, just like the shorts, they wick moisture away from you skin and help to keep you dry
The third thing is storage, men's jerseys have 3 large pockets in the back that are great for stuffing a plethora of handy items like your cell phone, first aid kit, glucometer for diabetics, snacks, extra water bottles, layers you need to shed in route, tire repair stuff. Women's jerseys will frequently have a couple of not near as functional pockets as will sleeveless triathlon jerseys. In the case of the tri jersey this is understandable as you have to swim in this jersey, but the women's???? come on, wake up women's jersey designers and start making jerseys that fit women and also have adequate storage!!
For this reason alone, women may consider wearing a men's jersey. I stuff so much stuff in my jersey pockets that I often look like a hoarding hamster!
Socks, should be technical but don't have to be cycling specific as running socks will frequently work very well in cycling shoes and have many of the same properties as cycling specific socks.
These are the basics, feel free to ask any questions or make any comments as you see fit.
The answer to a lot of questions on what to wear can be found here The Rules #14 - 18
I will be doing a cold weather specific clothing expose in the very near future, with cold weather approaching and all