The following are buzzwords I loathe and would be very happy if I never heard again:
at the end of the day (unless you mean 11:59 p.m., stop using this!)
buy-in (unless you are purchasing a part ownership in a business, cut it out!)
out of pocket (unless you are taking something literally out of your pocket, or you are paying for something out of that pocket. it is NOT correct to say "I'll be out of pocket." if you really mean "I'll be out of the office" or "I'll be out of contact".
These, among so many others, used repeatedly and incorrectly in the business domain, drive me absolutely NUTS!
Do you have "favorite buzzwords" you loathe? Let me know!