should

Used to issue an instruction (traditionally seen as carrying less force of authority than alternatives such as 'shall' or 'must').

Used to give advice or opinion that an action is, or would have been, beneficial or desirable.

(informal) With verbs such as 'see' or 'hear', usually in the second person, used to point out something remarkable in either a good or bad way.

In questions, asks what is correct, proper, desirable, etc.

Indicates that something is expected to have happened or to be the case now.

Will be likely to (become or do something); indicates a degree of possibility or probability that the stated thing will happen or be true in the future.

(auxiliary, subjunctive) Used to form a variant of the present subjunctive, expressing a state or action that is hypothetical, potential, mandated, etc.

(auxiliary) Simple past tense of shall.

(formal or literary) Used to express a conditional outcome.

(formal or literary outside certain combinations such as with 'imagine' or 'think') Used to impart a tentative, conjectural or polite nuance.

Used to express what the speaker would do in another person's situation, as a means of giving a suggestion or recommendation.