Functions of "Would"

Thanks for your answers in advance. Pls I would like someone to tell me why the use of "would" in the following sentences? 1. I would call you. 2. I would like you to give me some cake 3. When should we use "would", apart from its function as past tense of "will"? Once again, thanks for your answers.

1. to express a polite offer or request:
Would you like tea?
Would you like me to do it?
2.to describe a habitual past action:
Every evening I would walk in the garden.
3.used in speaking of something that will, may or might happen(eg. if a certain condition is met):
If I asked him to the party, would he come?
4.used to express a preference, opinoin etc politely:
I would do it this way.
5. used, said with emphasis, to express annoyance:
I've lost my car-keys-that would happen!
Hope that help you.