Learn Russian: Вот бы лежать под пальмой и не видеть снега. - If only I could lie under a palm tree and not see snow.

When Вот бы is followed by an infinitive, it expresses a general wish without a specific grammatical subject, translating roughly to 'If only it were possible to...'. If you wanted to explicitly name the subject, you would use the past tense: Вот бы я лежал... (If only I were lying...).

Both verbs here are imperfective. Why wouldn't we use perfective verbs for this wish?

The imperfective aspect is used because the speaker is wishing for a continuous, ongoing state (spending time lying down and continually not seeing snow). A perfective verb would imply a one-time, completed action, which completely ruins the vibe of an ongoing daydream.

Why is it не видеть снега (genitive) instead of не видеть снег (accusative)?

This is a great example of the 'genitive of negation'. When a verb is negated, its direct object is often put in the genitive case instead of the accusative. This is especially common with verbs of perception like видеть, and it emphasizes the absolute absence of the object ('not seeing any snow at all').

Just as a refresher, why does под take the instrumental case in под пальмой?

The preposition под takes the instrumental case when it describes a static location answering the question 'where?'. If the sentence described an action of moving to get under something, answering 'where to?', под would take the accusative case instead.