How can sentences be written so that the speaker takes responsibility for the feelings expressed?

In order for the speaker to take responsibility for the sentiments expressed, the speaker – that is, I – would have to be the subject of the sentence, and the sentences as they exist would have to become object clauses.  These clauses could then function as opinions expressed by the subject, modified by action verbs.  Treating them this way, we could transform the sentences

a. It's really annoying to have to wait for people.

b. You...

In order for the speaker to take responsibility for the sentiments expressed, the speaker – that is, I – would have to be the subject of the sentence, and the sentences as they exist would have to become object clauses.  These clauses could then function as opinions expressed by the subject, modified by action verbs.  Treating them this way, we could transform the sentences

a. It's really annoying to have to wait for people.

b. You never know what's going to happen with Marianne.

c. We really should get going.

b. Are you sure?

to read

a.  I think it’s really annoying to have to wait for people.

b.  I don’t think you can ever know what’s going to happen with Marianne.

c.  I think we really should get going.

d.  I don’t think you’re sure.

Another way to ensure the speaker is taking responsibility for these statements would be to simply substitute a first-person subject pronoun for the existing subject pronouns, thus replacing it, you, and we with I, and altering the subsequent verbs and phrases accordingly.  This works best with (a) and (b), resulting in:

a.  I get really annoyed when I have to wait for people.

b.  I never know what’s going to happen with Marianne.

With (c), the use of we implicitly includes the I of the speaker, and so one could argue that this sentence does not need to be changed, as it already implies some agency from the speaker, just with the assumed complicity of another party in the sentiment.

With (d), if one wanted to maintain a certain level of politeness, which the first example above does not, one could be a little bit wordy, saying something like I just want to check that you’re sure.  This maintains the agency of the speaker without the accusing tone adopted by the sentence I don’t think you’re sure.