Perhaps it isn't much of a surprise after all - if you pass through a sales floor on a Friday afternoon you may see a few more games of solitaire being played than deals being made. Most sales people know that asking prospects or customers to accept a quote, or decide on a purchase is a time intensive task, and engaging in these types of activities late on a Friday tends to yield less than spectacular results. Asking someone their opinion on the other hand, seems a good way to engage with a prospect or customer without putting much pressure on them before a weekend.
There are some exceptions to the rule (e.g. when a Friday lands on end of month/quarter/year, or during a big promotion push), but I always try to reserve Friday afternoons to talk with customers or prospects interested in Sage ACT!, strictly in a informational and research context. Friday afternoon calls are more often answered, and Friday afternoon meeting requests are more often accepted compared to any other time spot. Something about getting ready of the weekend and time away from the office tends to get people to reflect on recent activities and discuss their thoughts with a broader context.
Sometimes it's a challenge to get the energy going late on a Friday, but some of my best customer experiences have been open, honest conversations about ACT! late on a Friday. Developing a relationship with a customer usually takes time, but if you have a chance to chat with a couple of customers outside of a sales scenario, consider scheduling it on a Friday afternoon - you might be surprised how far you can advance an opportunity late in the week.