I see the mind as my 'life's work'. What it's condition will be like by the end of my life, that's the single most important thing. Dhamma practice brightens it, little by little; unwholesome actions darken it, even just by a little.
I can recall a place in the suttas where the Buddha says that one should see Virtue as an 'ornament' for the mind. In that sense, telling a deliberate lie, unless for some urgent life-threatening reason, is always going to have a 'net' negative effect, even if no-one (else) is harmed in any way by our lie. Yes, no-one was harmed by our little 'white lie', but our own mind
saw it! And so, it would be contaminating.
And no, I'm not perfect, either! So I'm not trying to sound preachy. I intuit that most of us could find some improvement we could make in the area of samma vaca. (?).
Regarding 'not wishing to hurt someone's feelings', let's look at an example from my own past. I was with my (now) ex at the time. She had just bought a new dress, but I did not know this. So when she asked me what I thought of it, I just stupidly blurted out the first thing that came into my mind - that I did not think so much of it. (Her response was less than pleased!). Now if I had been a bit more aware,
I could have just said 'it's alright' or 'yes, it's fine' instead, and side-stepped the issue of whether I 'liked' it or not. Because, truthfully, it is
fine - all functional clothing is 'fine' so long as it does it's job - and I would have kept the precept, but without hurting her feelings in the process. (Anyway, we live and learn!)
As for the question, 'does my butt look big in this?'
, that would take a whole new level of skill to negotiate...I guess we could say "well, 'big' is a relative term"
...but that's not going to go down well either, I feel...