Is it better to choose a garden site with a great environment and poor soil, or a site with great soil but a poor growing environment?

It is far easier to modify the soil than it is to modify the growing environment. If possible, choose the site with the most hours of sunlight. If the soil is poor quality, you can always modify it, or grow the garden in raised beds or containers.

I live in a dry area of the province, so I chose a garden site where water collects after a rain incidence. Why not take advantage of the free water rather than having to water the garden myself. Is this a good idea?

Potentially this is not a good choice. True, water will collect in low areas, and it is free, but if the water sits there and floods the area for a few days, that could seriously damage or even kill the garden plants. The other potential problem is that cold air collects in low areas, so that area may freezer earlier than areas of the yard that are higher. This could shorten the growing season for warm season crops like beans, cucumbers, squash, etc.

It is true that in windy areas, the garden soil will dry faster, so I chose a site with trees all around the garden, thinking that I would not have to water as often. Was that the right decision?

Potentially not. If there is no air movement at all in the garden area, the relative humidity will be higher and this can lead to an increase in the incidence of fungal diseases. A good example is that mostly likely you will see powdery mildew on your peas earlier in the summer than usual.

Last year, I planted raspberries on the hill side right by the house facing south. I did this because that area warms faster and thought I would get a longer growing season for the raspberries. This spring most of the plants started to grow then died.Why?

You are correct in saying the south facing slope warms faster but raspberries have a low endodormancy requirement, so they come out of dormancy earlier than many other fruits. Once they start growing they are sensitive to frost, so they may have started growing and were killed by later season frosts. It is a better idea to plant raspberries on a north or east facing slope. If you only have a south facing slope, you will need to shade the soil to keep it cold which will prevent the raspberries from starting to grow too early in the year.

I planted all my garden on the May long weekend, which is what my neighbors told me to do. Lots of the vegetables started to grow, but none of my zucchini, cucumbers or green beans grew at all. They never even came out of the ground. What happened?

Your neighbors should have told you to plant the cool season crops on the long weekend, but wait until early June when the soil was warmer, before planting the warm season crops. The three you mentioned are all warm season crops, and the seeds probably rotted in the soil before being able to germinate and emerge.