This pattern is used when the speaker is talking about a situation for which there are many reasons for it have come about, but the speaker only wishes to name one or two and leave the left unsaid.

- attaches to the plain style declarative form
- is less direct than 어서. Therefore, there is pattern can be used when you don't want to give a full explanation, i.e. as a softening strategy or with more disgression.
- in colloquial speech, the 해서 portion can be omitted but is then less emphatic (and more easily confused with the 고 that means "and")
- is usually as a response to a question

Examples:
기분 나쁘다고 해서, 화를 내면 안 됩니다./Even though you feel bad, you should not get angry.
품질 안 좋고 해서 그 물건을 사지 않았어요./It was of poor quality and so we didn't buy it (and there are other unstated reasons we didn't buy it).