Pleasant, agreeable.
You can use kind, friendly, or a word that describes exactly how they are nice, such as generous, forgiving, or whatever word(s) apply.
astounding
throw
Try being nice instead of calling anyone dumb.
gazing glaring
Another word for nice or kind to sound more professional in a thank you note could be polite or pleasant.
Briefed or enlightened could be used instead of informed. Other words could as well but it depends on the context of the statement.
friendly or kind :)
Items, or events
One word for motivated is determined.
good, excellent, pleasant, lovely, beautiful, agreeable, nice-looking, amiable,
You could use the word "constantly" instead of "always." Other alternatives include "invariably" or "perpetually," depending on the context. Each of these words conveys a sense of something happening without exception or interruption.