The Rule of Despite is: "(Not to be negative, but) managers must progress innovation, support workers' efforts and pursue great outcomes for clients, despite the circumstances in which they find themselves and their teams."
I find that many people see the barriers and not the enablers; in SWOT-speak, they see the weaknesses and threats, and not the strengths and opportunities.
Although this is a message much broader than 'facilitation', it is relevant to the facilitator at two levels.
Firstly, the old saying 'the show must go on' is frequently relevant for the facilitator. The laptop is in a tailspin of downloading updates and rebooting spontaneously; there are chairs but no tables for people's workbooks; the air-conditioner has broken down and sweat is dripping off your nose; your shoes are too small and your markers are all fuzzy; but the show must go on.
Secondly, in facilitating commitment, you may confront significant resistance due to external circumstances. Members of your audience may have been conditioned to be 'the devil's advocate' (by the way, I'm never sure where to put the apostrophe in that phrase - are they advocating on behalf of one or more devils?); or they may be having a bad day; or they may be resistant for many other reasons. Whatever the cause of resistance, it is important not to let too many excuses get in the way of progress.
Sometimes we need to ask people to commit, despite their circumstances.
I commend to you, Geoff's Law.