the knowing smile.
when Pink Milkshake no longer means strawberry ice cream.
when you know how to take the slack out of the e brake.
when you know what 13WL means, and why it is better than 13WE.
when you didn't know what an e locker was before buying it and now the first question is always "does it have the rear locker?"
when you know Highlander front mud flaps won't fit on your Limited.
when you realize every type of little plastic clip and fastener for your 15 year old truck is still available from the dealer, even the hood support grommet.
when on a friday evening your girlfriend gives a knowing smile as you start talking about your most recent upgrade or modification, because this is always the first thing you talk about once the evening has gone postcoital.