<span>Life is an adventure
</span>
The word with a negative connotation is discouraging.
When someone is discouraged, they are dispirited, disheartened, and with a lack of enthusiasm; this has a negative implication.
All other options have positive connotations, except maybe bulb, which is pretty neutral.
I hope this helps you!
A since the sense of fulfilment will bring about more encouragement to continue studies
