This is probably the important bit here!

One can probably talk about having a positive outlook being overall a good idea in life in many cases, but I'm also inclined to agree with you that experiencing the whole emotional spectrum when appropriate is also an enriching experience.

Just as long as you don't let certain emotions or feelings overwhelm you too much, e.g. getting used to being angry about something and focusing on it too much. Learning to let things go is probably also a useful skill, as is self reflection.