Honey is made from nectar/honeydew as a food stock for winter for the bees. The presence of flowers always differs, so the mix of nectar brought to the hive is always different, and therefore the taste changes. We have honey made mostly from:
Some flowers, if present in abundance, give the nectar a typical, recognisable taste, for example chestnut flowers. The same applies to honeydew.
Bees “seal” honey at 18% humidity to properly conserve it. It’s good to follow this advice and seal the jar well!
The crystallisation process is a normal, healthy process for most types of honey. Warm it gently to make it liquid again, without destroying its beneficial properties.