Whenever one is helping someone with a Linux problem, one cannot overstate the importance of checking the “easy” things first. What we think of as “easy” is very rarely so for the Linux beginner, and it’s also vital to never hold an oversight against him or her.
We had a LUG member who had for some time been asking some very intelligent questions about how to find a good Linux-compatible wireless adapter add-on for his laptop. While trying to help him with an unrelated issue, I happened to run /sbin/lspci and discovered he had a Broadcom 4318 card in the machine already, which he hadn’t known about! Obviously this was less than ideal but far from a disaster, and certainly had we bothered to ask the right questions off the bat, we could have saved him a significant amount of wifi-lessness.
Lesson learned: when helping others, don’t be afraid to be pedantic, as long as you are properly apologetic about it. The opposite fashion (and the greater geek tendency) is to assume knowledge that may not exist, so as not to improperly underestimate one’s audience. However, this tendency discounts the situational aspect in which someone is asking questions precisely because they are looking for that knowledge. Delivering it with authority and humility at the same time is a learned skill.