Here are two tweets giving us Mussar on the parshah from the Torah Temimah.
"@NishmaTweet: P. Vayiqra 1:1 Mussar 1 TT  don't enter pi'tom. Announce yourself first. Good etiquette, good psychology."
"@NishmaTweet: P. Vayiqra 1:1 Mussar 2 TT  don't talk or address someone w/o getting their approval first also Good etiquette & good psychology."
Thus, we see some Midrash Halachah offering us practical ethical behaviour:
Don't startle people by entering abruptly.
Don't talk or preach to people w/o asking their permission first.
Be considerate - and use wisdom when doing so.