A considerate request acknowledges the inconvenience without using gratitude as pressure.

Gratitude offered before an answer can be courtesy or it can be a trap, depending on the phrasing. Saying you know this is a lot to ask names the cost honestly and leaves the reply open. Saying you knew you could count on them, before they have replied, converts a request into an obligation and makes refusal a betrayal. The two sound similar and do opposite things.

Read your next ask before sending it and check whether a no would still be easy. If it would not, rewrite until the person could decline and nothing would be damaged.