Why do we say...

"Honestly..."
"The truth is..."
"In my humble opinion..."
"Literally..."
"Seriously..."

Why do we feel the need to preface our statements with such comments? Every time I hear myself say one of the examples above, I'm tempted to slap my forehead.  Would people be in doubt if I left those words out of my sentences?

"Honestly, I think not."
"The truth is, they probably wouldn't."

I'm not lying if I leave off the "honestly" and "the truth is."

What about this: "In my humble opinion, people shouldn't use such phrases."  By expressing my opinion, aren't I acknowledging it's my opinion and others might not agree? I believe I can do that with humility without using "humble."

"I literally just heard someone say this."  Again, would there be any doubt? When people say such things, do we wonder if they're speaking figuratively? I promise to take your word for it if you leave "literally" out of your sentence.  Same thing goes for "seriously."

Okay, I feel better.  There's my rant for the day.  If you have any examples to offer, feel free to share.  Even if none come to mind, I'd love to hear your comments.