For me it's a biggie - relationships based on trust etc - for my DH not so much:
tricky situation? - tell a lie to get out of it
don't want to do something? - lie to get out of it
feel guilty about something? - tell a lie to avoid conflict
I'm really struggling - caught him out in a few lies to me recently which in the grand scheme of things probably aren't massive (no OW or anything like that - more in the trying to get himself off the hook and also re: money) but it's made me question everything, can I trust anything he says?
Am I being a bit melodramatic?