Nothing important happened but Macgyver wanting to quit to settle down.
We see several flashbacks from episodes like the Pilot, the episode with the famous scenes with the map that helps Mac get out of trouble, the episode where he meets Penny and they escape from the airport, etc. Jack (in a disguise) brings Mac to the Phoenix Foundation and several friends he has met in the past are there. Kate Connolly, Penny Parker, Pete Thornton, et cetera. It was a filler episode. Mac wants to quit but realizes that every person, every friend he has is because he has met them in dangerous situations or while on mission. So I guess you know what happened at the end of the ep.