You seem to equate keeping a log to not doing dives or not being serious about diving. Keeping a log is a way to show you are serious about diving and presents some proof that you are as qualified as you say you are. I, too, find it more important to log failures than successes - those are nice also! But logging failures gives you something to work on in the future. Review you log book and remember, oh yeah last time I went deeper than I planned or I got lost cause I didn't navigate well - instant things to work on.