What's it like owning and riding bikes?

[Bennet]

What is good and bad about owning and riding a (motor)bike as a regular alternative to a car?

Having never even been on a bike, what should I know or consider before spending any money on lessons or buying one? I'm thoroughly naïve about this and I don't happen to know anyone who rides one that I can ask about it.

The sorts of questions I don't know the answers to are:
Are they really best kept for fun journeys and nice roads, or are they a viable car alternative for day to day use?
Is a thick, heavy leather suit essential for every journey?
Is it horribly sweaty wearing it in nice weather?
Are you stupid to use a bike in wet weather?
Do they get stolen a lot?
Is it difficult to find places you can safely leave them when out and about?
What else ought I consider before deciding if it's for me?

If anyone wants to just link me to some decent introductory reading material or a past thread, that would be fine. Google didn't turn up much.

Thanks.

[Bennet]

Many thanks for the responses. I'll do a CBT and see where things go.