し (Reasons)And, Giving reasons

Both give reasons, but the structure and emphasis differ. ことだし presents a reason as a settled or obvious circumstance that naturally justifies a decision, often sounding calm and explanatory, as in 雨も降っていることだし、今日は家にいよう ('Since it’s raining anyway, let’s stay home today.'). By contrast, し～し lists multiple reasons side by side, emphasizing accumulation rather than inevitability, as in 雨だし寒いし、出かけたくない ('It’s raining and cold, so I don’t want to go out.').

上に (literally, 'on top of') can be used as a slightly formal way to express 'in addition to (A), (B)', e.g. 安い上に、美味しい ('In addition to being inexpensive, it's tasty.'). While し～し is similar in that it lists multiple things, it specifically does so in the context of giving reasons for something, e.g. 安いし、美味しいし、一番好きなお店です ('It's inexpensive, it's tasty too, and so it's my favorite shop.').

じゃあるまいし is a combination of the まい form that is equivalent to ないだろう and し used to list reasons. Technically, it could be rephrased as じゃないだろうし, or even simply じゃないし for a more direct way of expressing the sentiment of 'You're/It's not (A), so...', e.g. 子どもじゃあるまいし ('You're not a child, so...').

し～し lists multiple reasons, similar to 'because of A, B, and so on' in English. In contrast, Adjective + て + B just connects adjectives. While it can imply the first quality supports the second (e.g. 甘くておいしい = 'sweet and delicious'), it doesn't suggest a broader conclusion. し often implies one, as in 甘いし、おいしいし, meaning 'It's sweet and delicious… (so I like it).'

Both し～し and から express reasons, similar to 'so' or 'because' in English. The reason (A) for outcome (B) is always followed by し or から, e.g. (A) し/から (B). The key difference is that から focuses on a single reason, while し～し lists multiple reasons. Even with one reason, し implies other unstated or implied reasons.

Both し～し and ので express reasons, similar to 'so' or 'because' in English, with the reason coming before し or ので. The main difference is that ので focuses on a single, objective reason, while し～し lists multiple reasons and often has a more personal or subjective feel. Even with one reason, し implies that there are other unstated or implied reasons.

し～し and とか～とか both list things, but with a different nuance. し～し lists reasons or causes, like 'because of things like (A) and (B)'. とか～とか simply lists items without implying they are a cause for something else, i.e. 'things like (A), (B), and so forth'. Also, とか～とか is very casual, while し～し will be found in both speech and writing.

Both forms can express reasons, but their usage differs. Verb[て] + B shows that the stated action is the direct reason for what follows, while し～し implies that multiple reasons exist, even if only one is mentioned. For example, 犯人が捕まって安心です ('I'm relieved because the criminal was caught.') vs. 犯人が捕まったし、安心です ('The criminal was caught, and I'm relieved.'), where the し version suggests there may be other factors for the relief.