In life as in death there are only two choices: to refuse or to accept. Denial of an explicit answer is 99.99% of the time an acceptance. So, what if you give you an armchair and ask you to have all pleasure or all the displeasure in accepting our proposal, without duress, without force, withour coercion?
Proposal: would you give your chair to me if I asked you?
I think there are three things you can do:
1. give me all the chair.
2. share the chair with me,
3. refuse the proposal.
All three choices are mutually exclusive, that means, you can't give me all your chair and still be sharing it with me neither can any of the two apply when you refuse to accept my proposal. So which do I think you will accept.
I SURE WANT YOU TO ACCEPT SOMETHING.
I assume you don't have another so you won't give me all your chair unless you are a character that is worth studying, unless I do what is not allowed: bully, force, harass or insult you? I assume you have only one chair.
Sharing the chair with me is a possibility if the width of the chair is more than that of your backside i.e there is extra space for me, but you could also refuse even if there is extra space for me. I believe either option makes you comfortable: sharing or refusing. If either option makes you comfortable, then if you refuse to share you'd have extra unused spaces on your chair which would implicitly incur costs on your person, either in the abstract or in the physical.
PRINCIPLE: according to the law of entropy, any matter left unused for some time tends to run to chaos, disorder or breakdown.
So on principle, where sharing and refusing makes you comfortable, just share and tell how you felt.