Questions & Answers about Мне удобно сидеть в этом кресле.
Why is it мне and not я?
Because this sentence uses an impersonal construction.
Russian often says things like:
- Мне удобно = It is comfortable/convenient for me
- Мне трудно = It is difficult for me
- Мне холодно = I am cold / It feels cold to me
So мне is in the dative case, showing the person who experiences the feeling or situation.
Literally, the structure is closer to To me, it is comfortable to sit in this armchair than to I sit comfortably.
What exactly is удобно here?
Удобно means comfortable, convenient, or easy to use/be in, depending on context.
In this sentence, it describes the situation as comfortable for the speaker. Grammatically, words like удобно, трудно, легко, холодно, жарко are often treated as predicative words or category-of-state words in Russian. They commonly appear in impersonal sentences.
So here:
- мне = for me
- удобно = comfortable/convenient
- сидеть = to sit
Together: It is comfortable for me to sit...