"Almost" never killed a fly means that almost is not good enough, and it’s not a valid excuse. You either do something or you don’t do it, there is no in-between.
Can you give some examples of such ambiguous sayings?
"almost" is of such thing I hate at work,something like "almost done", "almost good" to me is not done, bad; regardless some are really 'almost'. The second best in my list would be: I think so.
Especially the persons around me using 'I think so' the most towards uncertainties are the ones without solid knowledges but their common sense or instinct I'd prefer to say.
Personally, I'd always try to avoid using my subjective consciousness to judge objective matters. Yes, I have to used 'I think so' in many cases, but when I have to say so meaning this is from my subjective, no accuracy guaranteed.
When serious, if someone said 'I think so', I often got back 'give me enough proofs before we can make a move'----of course to my subordinates; and vice versa, I'd prefer to have enough clues before speaking so that when being asked 'you think so?' I can answer not just I think so, I actually saw something or had some evidences.