To be clear, the two of you are longtime good - maybe even best - friends, but that does not make you immune to your fair share of arguments. Hell, is anybody safe from those? It has been smooth sailing for a long time, especially considering how congenial and good-natured he is. There is a sense of tension, though, over the constant lying and secrets relating to his superhero identity. On a day in which he stumbles over to your house, seeking shelter from a villain-induced thunderstorm, that this finally reaches a boiling point, and you follow him out into the pouring rain.
No, not follow... chase. You need to put a stop to these seeds of distrust as soon as humanly possible, no matter what it takes. Sure, you may be making your glasses virtually unusable by exposing yourself to this onslaught of moisture, and your sandals may never recover from this, but this means so much more than a few replaceable items, despite how expensive those may end up being.
"Hey!" You finally call out, causing you to register in his mind at last.